MBBS First Professional (CBME) – Anatomy Paper I (August 2025)

Model Answers

I. Essay (10 Marks)

Question 1

A 62-year-old bus conductor came to the surgery OPD with complaints of pain in his right leg for the past 6 months. Clinical examination revealed dilated, tortuous veins in the medial aspect of the right lower limb and was diagnosed to have varicose veins.

a) Describe the formation, course and relations, tributaries and termination of the great saphenous vein. (1+2+3+1 Marks)

Answer

Formation

Formed by the union of the medial marginal vein with the medial end of the dorsal venous arch of the foot.
Begins in front of the medial malleolus.

Course

Passes anterior to the medial malleolus.
Ascends along the medial side of the leg.
Passes behind the medial condyle of the femur.
Ascends along the medial side of the thigh.
Pierces the cribriform fascia at the saphenous opening.
Terminates in the femoral vein.

Relations

In the Leg

Lies in superficial fascia.
Accompanied by the saphenous nerve.

At the Knee

Passes behind the medial condyle.

In the Thigh

Lies superficial to fascia lata.
Pierces the cribriform fascia before entering the femoral vein.

Tributaries

Superficial epigastric vein
Superficial circumflex iliac vein
Superficial external pudendal vein
Posterior arch vein
Numerous cutaneous veins

Termination

Opens into the femoral vein through the saphenous opening.

b) Explain the anatomical basis of varicose veins. (3 Marks)

Answer

Varicose veins are permanently dilated, elongated and tortuous superficial veins.

Anatomical Basis

Failure of venous valves.
Weakening of vein wall.
Increased venous pressure.
Blood refluxes from deep veins into superficial veins through incompetent perforators.
Great saphenous vein is commonly affected.

Predisposing Factors

Prolonged standing
Pregnancy
Obesity
Old age

Clinical Features

Dilated tortuous veins
Pain and heaviness
Edema
Venous ulcers near medial malleolus

II. Reasoning Out Short Notes (5 Marks Each)

Question 2

Intramuscular injection in the arm may lead to inability to abduct the arm. Give reasons for the above statement.

Answer

Intramuscular injection given incorrectly in the deltoid region may injure the axillary nerve.
The axillary nerve winds around the surgical neck of the humerus through the quadrangular space.
It supplies:
- Deltoid
- Teres minor
Deltoid is responsible for abduction of the arm from 15° to 90°.
Injury causes:
- Loss of abduction
- Flattening of shoulder
- Wasting of deltoid
- Loss of sensation over the regimental badge area.

Question 3

Haematemesis occurs in portal hypertension – Reason out.

Answer

Portal hypertension increases pressure in the portal venous system.

Portosystemic Anastomosis

Occurs at:

Lower end of oesophagus
Umbilicus
Anal canal

At the lower end of oesophagus:

Portal vein → Left gastric vein
Systemic vein → Oesophageal veins → Azygos vein

Raised portal pressure produces:

Oesophageal varices
Rupture of varices
Massive haematemesis

III. Short Notes (6 Marks Each)

Question 4

Write a short note on Anatomical Snuff Box and its applied aspects.

Answer

Boundaries

Lateral

Abductor pollicis longus
Extensor pollicis brevis

Medial

Extensor pollicis longus

Floor

Scaphoid
Trapezium

Roof

Skin
Superficial fascia

Radial artery
Cephalic vein
Superficial branch of radial nerve

Applied Anatomy

Scaphoid fracture
Radial artery palpation
Tenderness in anatomical snuff box

Question 5

Write a short note on Cadaver as the First Teacher.

Answer

Provides three-dimensional understanding of anatomy.
Helps correlate anatomy with clinical practice.
Develops surgical skills.
Improves manual dexterity.
Teaches professionalism and ethics.
Encourages respect for the human body.
Forms the foundation of medical education.

Question 6

Write a short note on Midgut Rotation.

Answer

Midgut rotates around the superior mesenteric artery.

Stages

Physiological herniation.
90° anticlockwise rotation.
Return to abdominal cavity.
Additional 180° anticlockwise rotation.

Total rotation = 270° anticlockwise.

Applied Anatomy

Malrotation
Volvulus
Internal hernia

Question 7

Write a short note on Histological differences between lymph node and spleen.

Answer

Lymph Node	Spleen
Filters lymph	Filters blood
Cortex and medulla	White pulp and red pulp
Afferent lymphatics present	No afferent lymphatics
Medullary cords present	Splenic cords present
Hilum present	Hilum present

Question 8

Write a short note on Synovial Joint.

Answer

Features

Articular cartilage
Synovial membrane
Joint cavity
Synovial fluid
Fibrous capsule
Ligaments

Types

Plane
Hinge
Pivot
Condyloid
Saddle
Ball-and-socket

Functions

Free movement
Shock absorption
Stability

Question 9

Write a short note on Superficial Perineal Pouch.

Answer

Boundaries

Roof – Perineal membrane
Floor – Colles’ fascia

Contents in Male

Root of penis
Bulb of penis
Crura
Bulbospongiosus muscle
Ischiocavernosus muscle
Superficial transverse perineal muscle
Pudendal vessels and nerves

Contents in Female

Clitoris
Vestibular bulbs
Greater vestibular glands
Associated muscles

Question 10

Write a short note on the Anatomical basis of Carpal Tunnel Syndrome.

Answer

Cause

Compression of the median nerve beneath the flexor retinaculum.

Causes

Rheumatoid arthritis
Pregnancy
Diabetes mellitus
Repetitive wrist movements

Clinical Features

Pain
Tingling
Numbness
Thenar muscle wasting
Ape thumb deformity

Question 11

Write a short note on Lymphatic drainage of the stomach and its applied aspects.

Answer

Lymphatic Drainage

Left gastric lymph nodes
Right gastric lymph nodes
Left gastroepiploic lymph nodes
Right gastroepiploic lymph nodes
Pancreaticosplenic lymph nodes
Pyloric lymph nodes

All ultimately drain into the coeliac lymph nodes.

Applied Anatomy

Spread of gastric carcinoma through lymphatics.
Enlargement of Virchow’s (left supraclavicular) node may occur in advanced gastric cancer.

Question 12

Write a short note on Longitudinal arch of foot and factors maintaining it.

Answer

Types

Medial longitudinal arch
Lateral longitudinal arch

Factors Maintaining the Arch

Passive Factors

Shape of bones
Plantar aponeurosis
Spring ligament
Long plantar ligament

Active Factors

Tibialis anterior
Tibialis posterior
Flexor hallucis longus
Flexor digitorum longus

Applied Anatomy

Flat foot (Pes planus)

Question 13

Write a short note on Prostate gland and its applied aspects.

Answer

Situation

Lies below the urinary bladder.
Surrounds the prostatic urethra.

Lobes

Anterior lobe
Median lobe
Posterior lobe
Two lateral lobes

Blood Supply

Inferior vesical artery
Middle rectal artery

Venous Drainage

Prostatic venous plexus

Applied Anatomy

Benign prostatic hyperplasia (BPH)
Carcinoma of the prostate
Urinary retention
Digital rectal examination (DRE)
Transurethral resection of the prostate (TURP)

MBBS First Professional (CBME) – Anatomy Paper II (August 2025)

Essay & Short Notes – Model Answers

Based on the uploaded question paper.

I. Essay (10 Marks)

Question 1

A 67-year-old male, known case of uncontrolled hypertension and diabetes, was brought to the hospital with complaints of sudden onset of slurred speech and inability to move the right side of the body and limbs. Clinical examination revealed increased muscle tone and tendon reflexes and positive Babinski sign on the affected side. MRI showed a vascular lesion on white matter of the left cerebral hemisphere. He was diagnosed with internal capsule lesion.

a) Describe the parts and relations of the internal capsule, arrangement of fibres and arterial supply of the internal capsule. (2+3+3 Marks)

Answer

Definition

The internal capsule is a compact band of projection fibers situated between the basal ganglia and thalamus, carrying ascending and descending nerve fibers between the cerebral cortex and lower centers.

Parts

Anterior limb
Genu
Posterior limb
Retrolentiform part
Sublentiform part

Relations

Anterior limb

Medial – Head of caudate nucleus
Lateral – Lentiform nucleus

Genu

Junction of anterior and posterior limbs.

Posterior limb

Medial – Thalamus
Lateral – Lentiform nucleus

Retrolentiform part

Posterior to lentiform nucleus

Sublentiform part

Inferior to lentiform nucleus

Arrangement of Fibres

Anterior limb

Frontopontine fibres
Anterior thalamic radiations

Genu

Corticonuclear (corticobulbar) fibres

Posterior limb

Corticospinal fibres
Sensory fibres (thalamocortical)
Corticorubral fibres

Retrolentiform part

Optic radiation
Parietopontine fibres

Sublentiform part

Auditory radiation
Temporopontine fibres

Arterial Supply

Anterior limb: Medial striate artery (recurrent artery of Heubner) and lateral striate arteries
Genu: Lateral striate arteries
Posterior limb: Lateral striate arteries and anterior choroidal artery
Retrolentiform part: Posterior cerebral artery
Sublentiform part: Anterior choroidal artery and posterior cerebral artery

b) Explain the anatomical basis of the clinical features in this condition. (2 Marks)

Answer

The posterior limb of the internal capsule contains corticospinal fibres controlling voluntary movements of the opposite side of the body.

A vascular lesion involving the left internal capsule damages these descending motor fibres, resulting in:

Contralateral (right-sided) hemiplegia
Upper motor neuron signs
- Increased muscle tone (spasticity)
- Hyperactive tendon reflexes
- Positive Babinski sign
Slurred speech (dysarthria) due to involvement of corticobulbar fibres in the genu.

Hypertension commonly causes rupture of lenticulostriate arteries, producing capsular stroke.

II. Reasoning Out Short Notes (5 Marks Each)

Question 2

Genioglossus is the safety muscle of tongue – Reason out.

Answer

The genioglossus is the chief protrusor muscle of the tongue.

It arises from the superior mental spine of the mandible.
It is supplied by the hypoglossal nerve (CN XII).
On contraction, it protrudes and depresses the tongue.

Reason

During unconsciousness or general anaesthesia, paralysis of the genioglossus allows the tongue to fall backwards.
The tongue may obstruct the airway and cause respiratory difficulty.
Contraction of the genioglossus pulls the tongue forward, keeping the airway open.

Hence, the genioglossus is called the “safety muscle of the tongue.”

Question 3

Black eye occurs in injury to scalp – Reason out.

Answer

A black eye (periorbital ecchymosis) is caused by accumulation of blood in the eyelids following scalp injury.

Anatomical Basis

Blood from the scalp collects in the loose areolar tissue (dangerous area) of the scalp.
It cannot spread posteriorly because the occipitalis muscle is attached to bone.
Anteriorly, the frontalis muscle has no bony attachment.
Therefore, blood tracks into the eyelids through the loose connective tissue.
The eyelids become swollen and discolored, producing a black eye.

III. Short Notes (6 Marks Each)

Question 4

Write a short note on Pharyngeal Arches.

Answer

Pharyngeal arches are mesodermal structures that appear during the 4th week of embryonic development.
Each arch contains:
- Cartilage
- Muscle
- Cranial nerve
- Artery (aortic arch)

Derivatives

First arch: Muscles of mastication, maxilla, mandible; CN V.
Second arch: Muscles of facial expression; CN VII.
Third arch: Stylopharyngeus; CN IX.
Fourth & Sixth arches: Muscles of pharynx and larynx; CN X.

Applied Anatomy

Branchial cyst
Branchial fistula
Congenital anomalies

Question 5

Write a short note on Principles of Communication.

Answer

Principles of effective communication include:

Active listening
Empathy
Respect
Confidentiality
Clear and simple language
Appropriate verbal and non-verbal communication
Feedback
Patient-centred approach
Professional behaviour

Importance

Builds doctor–patient relationship
Improves compliance
Reduces misunderstandings

Question 6

Write a short note on Interior of Larynx.

Answer

The interior of the larynx extends from the laryngeal inlet to the lower border of the cricoid cartilage.

Divisions

Vestibule
Ventricle
Infraglottic cavity

Important Features

Vestibular folds (false vocal cords)
Vocal folds (true vocal cords)
Rima glottidis
Laryngeal ventricle

Applied Anatomy

Laryngoscopy
Vocal cord paralysis
Laryngeal carcinoma

Question 7

Write a short note on Histology of Tongue.

Answer

Covered by stratified squamous epithelium.
Skeletal muscle fibres arranged in three planes.
Papillae:
- Filiform
- Fungiform
- Circumvallate
- Foliate
Taste buds present on fungiform, foliate, and circumvallate papillae.
Lingual glands present in submucosa.

Question 8

Write a short note on Phrenic Nerve.

Answer

Origin

Ventral rami of C3, C4, C5 (“C3, 4, 5 keep the diaphragm alive”).

Course

Descends on the anterior surface of scalenus anterior.
Enters the thorax.
Passes anterior to the root of the lung.
Ends in the diaphragm.

Supply

Motor: Diaphragm
Sensory: Fibrous pericardium, mediastinal pleura, diaphragmatic pleura, central diaphragmatic peritoneum.

Applied Anatomy

Phrenic nerve palsy causes diaphragmatic paralysis.
Referred pain to the shoulder (C4 dermatome).

Question 9

Describe the cut section of the medulla at the pyramidal level.

Answer

Structures seen include:

Pyramids
Corticospinal tracts
Inferior olivary nucleus
Medial lemniscus
Hypoglossal nucleus
Dorsal motor nucleus of vagus
Medial longitudinal fasciculus
Reticular formation
Fourth ventricle

Applied Anatomy

Medial medullary syndrome
Lateral medullary (Wallenberg) syndrome

Question 10

Write a short note on Oesophagus and its applied anatomy.

Answer

Extent

C6 to T11

Constrictions

Cricopharyngeal junction
Arch of aorta
Left main bronchus
Diaphragmatic hiatus

Blood Supply

Inferior thyroid artery
Aortic branches
Left gastric artery

Applied Anatomy

Foreign body impaction
Oesophageal varices
Carcinoma
Hiatus hernia

Question 11

Write a short note on Palatine Tonsil and its clinical importance.

Answer

Situation

Tonsillar fossa between the palatoglossal and palatopharyngeal arches.

Blood Supply

Tonsillar branch of facial artery (chief)
Ascending palatine
Ascending pharyngeal
Dorsal lingual branches

Clinical Importance

Tonsillitis
Tonsillectomy
Risk of haemorrhage
Referred ear pain via glossopharyngeal nerve

Question 12

Write a short note on Thoracic Duct and its applied aspects.

Answer

Origin

Cisterna chyli (L1–L2)

Course

Passes through the aortic hiatus.
Ascends in the posterior mediastinum.
Terminates at the junction of the left internal jugular and left subclavian veins.

Areas Drained

Entire body except the right upper quadrant.

Applied Anatomy

Chylothorax
Injury during neck surgery
Lymphatic obstruction

Question 13

Write a short note on Blood Supply of the Thyroid Gland and its surgical importance.

Answer

Arterial Supply

Superior thyroid artery (external carotid artery)
Inferior thyroid artery (thyrocervical trunk)
Thyroid ima artery (occasionally)

Venous Drainage

Superior thyroid vein
Middle thyroid vein
Inferior thyroid vein

Surgical Importance

Ligate the superior thyroid artery close to the gland to avoid injury to the external laryngeal nerve.
Ligate the inferior thyroid artery away from the gland to protect the recurrent laryngeal nerve.
Care is required to preserve the parathyroid glands during thyroid surgery.

MBBS First Year – Anatomy I (August 2019)

Solved Question Paper

I. Essay (10 Marks)

1. Describe in detail the brachial plexus including its formation, branches, and distribution. Add a note on its applied anatomy.

Definition

The brachial plexus is a network of nerves formed by the anterior (ventral) rami of C5, C6, C7, C8 and T1 spinal nerves. It supplies the upper limb.

Formation

Roots (5):

Trunks (3):

Upper trunk = C5 + C6
Middle trunk = C7
Lower trunk = C8 + T1

Divisions (6):
Each trunk divides into:

Anterior division
Posterior division

Cords (3):
Named according to their relation to the second part of the axillary artery.

Lateral cord = Anterior divisions of upper and middle trunks
Medial cord = Anterior division of lower trunk
Posterior cord = Posterior divisions of all three trunks

Branches

A. Branches from Roots

Dorsal scapular nerve
Long thoracic nerve

B. Branches from Upper Trunk

Suprascapular nerve
Nerve to subclavius

C. Branches from Lateral Cord

Lateral pectoral nerve
Musculocutaneous nerve
Lateral root of median nerve

D. Branches from Medial Cord

Medial pectoral nerve
Medial cutaneous nerve of arm
Medial cutaneous nerve of forearm
Ulnar nerve
Medial root of median nerve

E. Branches from Posterior Cord

Upper subscapular nerve
Thoracodorsal nerve
Lower subscapular nerve
Axillary nerve
Radial nerve

Distribution

Musculocutaneous nerve

Anterior compartment of arm
Lateral forearm skin

Median nerve

Most flexor muscles of forearm
Thenar muscles
Lateral 3½ digits

Ulnar nerve

FCU
Medial FDP
Most intrinsic hand muscles
Medial 1½ fingers

Axillary nerve

Deltoid
Teres minor
Skin over shoulder

Radial nerve

Extensor muscles of arm and forearm
Posterior arm and forearm
Dorsum of hand

Applied Anatomy

Erb’s palsy (C5–C6 injury)
- Waiter’s tip deformity
Klumpke’s palsy (C8–T1 injury)
- Claw hand
- May be associated with Horner syndrome
Long thoracic nerve injury
- Winging of scapula
Axillary nerve injury
- Loss of shoulder abduction
Radial nerve injury
- Wrist drop

II. Short Notes (4 Marks Each)

1. Inguinal Canal

Definition
An oblique 4 cm passage in the lower anterior abdominal wall.

Extent

Deep inguinal ring
Superficial inguinal ring

Walls

Anterior: External oblique aponeurosis
Posterior: Transversalis fascia
Roof: Internal oblique & transversus abdominis
Floor: Inguinal ligament

Contents
Male:

Spermatic cord
Genital branch of genitofemoral nerve

Female:

Round ligament of uterus
Genital branch of genitofemoral nerve

Applied anatomy

Indirect inguinal hernia
Direct inguinal hernia

2. Development and Microstructure of Urinary Bladder

Development

Endoderm of vesicourethral canal forms mucosa.
Trigone develops from mesonephric ducts.
Muscle and connective tissue arise from splanchnic mesoderm.

Microstructure

Transitional epithelium (urothelium)
Lamina propria
Detrusor muscle (three layers)
Adventitia/Serosa

3. Dorsalis Pedis Artery

Origin
Continuation of anterior tibial artery.

Course
Runs on dorsum of foot to first intermetatarsal space.

Branches

Lateral tarsal
Medial tarsal
Arcuate
First dorsal metatarsal
Deep plantar artery

Clinical importance

Palpation of dorsalis pedis pulse.
Peripheral arterial disease assessment.

4. Inversion and Eversion of Foot

Inversion

Joint

Subtalar
Transverse tarsal

Muscles

Tibialis anterior
Tibialis posterior

Nerve
Deep and tibial nerves

Eversion

Muscles

Fibularis longus
Fibularis brevis
Fibularis tertius

Nerve
Superficial fibular nerve

Applied

Common ankle sprains occur due to inversion.

5. Lobes of Prostate and Applied Anatomy

Lobes

Anterior
Median
Posterior
Right lateral
Left lateral

Applied Anatomy

Benign prostatic hyperplasia mainly affects median lobe.
Carcinoma commonly affects posterior lobe.
Posterior lobe examined by digital rectal examination.

III. Short Answers (2 Marks Each)

1. Fibrous Joint

Bones joined by fibrous tissue.
No joint cavity.
Examples: Sutures, syndesmosis, gomphosis.

2. Superficial Palmar Arch

Mainly formed by ulnar artery.
Completed by superficial palmar branch of radial artery.
Supplies palm and fingers.

3. Boundaries of Femoral Triangle

Superior: Inguinal ligament
Medial: Adductor longus
Lateral: Sartorius
Floor: Iliopsoas and pectineus
Roof: Fascia lata

4. Cutaneous Innervation of Sole

Medial plantar nerve
Lateral plantar nerve
Medial calcaneal branches of tibial nerve

5. Parts of Uterine Tube

Infundibulum
Ampulla
Isthmus
Intramural (uterine) part

6. Varicocele

Dilatation of pampiniform venous plexus.
More common on the left side.
Causes infertility and scrotal pain.

7. Flexor Retinaculum of Leg

Attachments

Medial malleolus
Calcaneus

Structures passing deep
(Tom, Dick And Very Nervous Harry)

Tibialis posterior
Flexor digitorum longus
Posterior tibial artery
Tibial nerve
Flexor hallucis longus

8. Space of Retzius

Retropubic (prevesical) space.
Between pubic symphysis and urinary bladder.
Filled with loose connective tissue.

9. Shoemaker’s Line

Line joining anterior superior iliac spine to greater trochanter.
Used to assess hip dislocation and neck of femur fractures.

10. Contents of Rectus Sheath

Above arcuate line:

Rectus abdominis
Pyramidalis
Superior epigastric vessels
Inferior epigastric vessels
Terminal parts of thoracoabdominal nerves (T7–T12)

MBBS First Year – Anatomy II (August 2019)

Solved Question Paper

The uploaded paper consists of one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Describe in detail about the Parotid gland. Add a note on its applied anatomy.

Definition

The parotid gland is the largest of the major salivary glands. It is a purely serous salivary gland situated below and in front of the external ear in the parotid region.

Situation

Between the ramus of mandible and mastoid process.
Occupies the parotid bed.

Shape

Pyramidal
Apex directed downward
Base directed upward

Coverings

True capsule (condensed connective tissue)
False capsule (parotid sheath) derived from deep cervical fascia

Relations

Base

External acoustic meatus
Temporomandibular joint

Apex

Over posterior belly of digastric

Superficial Surface

Skin
Superficial fascia
Great auricular nerve

Anteromedial Surface

Ramus of mandible
Masseter
Medial pterygoid

Posteromedial Surface

Mastoid process
Sternocleidomastoid
Posterior belly of digastric
Styloid process and its muscles

Structures within the gland (Superficial to Deep)

Mnemonic: Facial Nerve – Retromandibular Vein – External Carotid Artery

Facial nerve
Retromandibular vein
External carotid artery (divides into superficial temporal and maxillary arteries)

Parotid Duct (Stensen’s duct)

About 5 cm long
Emerges from anterior border
Crosses masseter
Turns medially
Pierces buccinator
Opens opposite upper second molar tooth

Blood Supply

External carotid artery
Superficial temporal artery
Maxillary artery

Venous Drainage

Retromandibular vein

Lymphatic Drainage

Parotid lymph nodes
Deep cervical lymph nodes

Nerve Supply

Secretomotor

Glossopharyngeal nerve (IX)
Tympanic nerve
Lesser petrosal nerve
Otic ganglion
Auriculotemporal nerve

Sensory

Auriculotemporal nerve
Great auricular nerve

Sympathetic

External carotid plexus

Functions

Secretion of serous saliva
Begins carbohydrate digestion
Lubricates food
Maintains oral hygiene

Applied Anatomy

Mumps (viral parotitis)
Parotid abscess
Parotid tumour (pleomorphic adenoma)
Facial nerve injury during parotid surgery causing facial paralysis
Frey’s syndrome (gustatory sweating)
Parotid duct obstruction and sialolithiasis

II. Write Notes (4 Marks Each)

1. Cavernous Sinus

Situation

On either side of the body of sphenoid bone.

Internal carotid artery
Abducent nerve (VI)

Structures in lateral wall

Oculomotor nerve (III)
Trochlear nerve (IV)
Ophthalmic nerve (V1)
Maxillary nerve (V2)

Tributaries

Superior ophthalmic vein
Inferior ophthalmic vein
Superficial middle cerebral vein

Applied Anatomy

Cavernous sinus thrombosis
Spread of infection from dangerous area of face
Ophthalmoplegia

2. Microstructure of Tongue

Layers:

Stratified squamous epithelium
Lamina propria
Skeletal muscle bundles in three planes
Minor salivary glands

Papillae:

Filiform
Fungiform
Circumvallate
Foliate

Taste buds present on:

Fungiform
Circumvallate
Foliate papillae

3. Intercostal Space

Boundaries

Between adjacent ribs.

Muscles

External intercostal
Internal intercostal
Innermost intercostal

Neurovascular Bundle

(VAN)

Vein
Artery
Nerve

Located in costal groove.

Functions:

Respiration
Protection of thoracic organs

4. Recurrent Laryngeal Nerve

Origin:

Branch of vagus nerve.

Course:

Right loops around subclavian artery.
Left loops around arch of aorta.

Supply:

Motor to all intrinsic muscles of larynx except cricothyroid.
Sensory below vocal cords.

Applied Anatomy:

Injury during thyroid surgery
Hoarseness of voice
Vocal cord paralysis

5. Relations of Thyroid Gland

Lateral

Sternothyroid
Sternohyoid
Superior belly of omohyoid
Sternocleidomastoid

Medial

Trachea
Larynx
Pharynx
Oesophagus
Recurrent laryngeal nerve

Posterior Border

Parathyroid glands
Inferior thyroid artery

Applied:

Thyroidectomy
Goitre
Recurrent laryngeal nerve injury

III. Short Answers (2 Marks Each)

1. Branches of Internal Thoracic Artery

Pericardiacophrenic artery
Anterior intercostal arteries
Perforating branches
Musculophrenic artery
Superior epigastric artery

2. Wallenberg Syndrome

Lateral medullary syndrome due to occlusion of the posterior inferior cerebellar artery (PICA).

Features:

Dysphagia
Hoarseness
Vertigo
Ipsilateral facial sensory loss
Contralateral body pain and temperature loss

3. Contents of Posterior Mediastinum

Descending thoracic aorta
Oesophagus
Thoracic duct
Azygos vein
Vagus nerves
Sympathetic trunks

4. Pterygopalatine Ganglion

Largest parasympathetic ganglion of head.
Suspended from maxillary nerve (V2).
Secretomotor fibres to lacrimal gland, nasal glands and palatine glands.

5. Formation of Superior Vena Cava

Formed by the union of:

Right brachiocephalic vein
Left brachiocephalic vein

Behind the lower border of the first right costal cartilage.

6. Bell’s Palsy

Lower motor neuron paralysis of the facial nerve.

Features:

Deviation of mouth
Inability to close eye
Loss of forehead wrinkles
Drooping of angle of mouth

7. Derivatives of Second Pharyngeal Arch

Muscles:

Muscles of facial expression
Stapedius
Stylohyoid
Posterior belly of digastric

Nerve:

Facial nerve (VII)

Skeletal derivatives:

Stapes
Styloid process
Lesser horn of hyoid
Upper body of hyoid

8. Structures Forming the Limbic System

Cingulate gyrus
Parahippocampal gyrus
Hippocampus
Amygdaloid body
Fornix
Mammillary body

9. Development of Pituitary Gland

Anterior pituitary (Adenohypophysis): develops from Rathke’s pouch (oral ectoderm).
Posterior pituitary (Neurohypophysis): develops from the infundibulum (neuroectoderm of diencephalon).

10. Transverse Sinus of Pericardium

A passage between:

Ascending aorta and pulmonary trunk (anteriorly)
Superior vena cava (posteriorly)

Clinical importance: Used by cardiac surgeons to clamp the great arteries during open-heart surgery.

MBBS First Year – Physiology including Biophysics I (August 2019)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Discuss the molecular basis of skeletal muscle contraction. Add a note on Rigor Mortis.

Introduction

Skeletal muscle contraction occurs by the Sliding Filament Theory, proposed by Huxley. Muscle shortens due to sliding of actin filaments over myosin filaments without change in their length.

Molecular Basis of Skeletal Muscle Contraction

1. Neuromuscular Transmission

Nerve impulse reaches motor end plate.
Acetylcholine (ACh) is released.
ACh binds nicotinic receptors.
End plate potential is generated.
Muscle action potential spreads over sarcolemma and T-tubules.

2. Release of Calcium

Depolarization activates dihydropyridine (DHP) receptors.
Ryanodine receptors on sarcoplasmic reticulum open.
Calcium ions are released into sarcoplasm.

3. Role of Troponin and Tropomyosin

Calcium binds Troponin C.
Troponin changes its configuration.
Tropomyosin moves away from actin.
Myosin-binding sites on actin become exposed.

4. Cross-Bridge Cycle

Energized myosin head (ADP + Pi attached) binds actin.
Pi is released.
Power stroke occurs.
ADP is released.
ATP binds myosin causing detachment.
ATP is hydrolysed to ADP + Pi.
Myosin head is re-cocked.
Cycle repeats while calcium and ATP are available.

5. Relaxation

Calcium actively pumped back into sarcoplasmic reticulum by SERCA pump.
Calcium dissociates from Troponin C.
Tropomyosin again covers actin.
Cross-bridge formation stops.
Muscle relaxes.

Sliding Filament Changes

Sarcomere shortens.
I-band decreases.
H-zone decreases/disappears.
A-band remains constant.

Rigor Mortis

Definition

Rigor mortis is the postmortem stiffening of muscles due to depletion of ATP.

Mechanism

ATP production stops after death.
Calcium leaks into sarcoplasm.
Actin and myosin form permanent cross-bridges.
Absence of ATP prevents separation of actin and myosin.
Muscle becomes rigid.

Time Course

Begins: 1–2 hours
Complete: 6–12 hours
Persists: 24–36 hours
Disappears due to autolysis and putrefaction.

Medicolegal Importance

Helps estimate time since death.
Indicates body position after death.
Useful in forensic investigations.

II. Write Notes (4 Marks Each)

1. Complement System for Antibody Action

Definition

Complement is a group of plasma proteins that enhance antibody-mediated immunity.

Classical Pathway

Activated by antigen-antibody complexes.
Begins with C1 activation.

Functions

Cell lysis (Membrane Attack Complex, C5b–C9)
Opsonization (C3b)
Chemotaxis (C5a)
Inflammation (C3a, C5a)
Immune complex clearance

2. Non-Excretory Functions of Kidneys

Erythropoietin production
Renin secretion
Activation of Vitamin D (Calcitriol)
Gluconeogenesis
Regulation of blood pressure
Regulation of calcium and phosphate metabolism
Hormone degradation

3. Glucose Transporters

Transporter	Site	Function
GLUT-1	RBC, Brain	Basal glucose uptake
GLUT-2	Liver, Pancreas	Bidirectional transport
GLUT-3	Brain	High-affinity glucose uptake
GLUT-4	Skeletal muscle, Adipose tissue	Insulin-dependent uptake
GLUT-5	Intestine	Fructose transport

4. Steps in Spermatogenesis

Spermatogonia (mitosis)
Primary spermatocyte
Meiosis I
Secondary spermatocyte
Meiosis II
Spermatids
Spermiogenesis
Mature spermatozoa

Occurs in seminiferous tubules under FSH and testosterone.

5. Erythroblastosis Fetalis

Definition

Hemolytic disease of the newborn caused by Rh incompatibility.

Cause

Rh-negative mother carrying Rh-positive fetus.

Features

Severe anemia
Jaundice
Hydrops fetalis
Kernicterus

Prevention

Anti-D immunoglobulin administered to Rh-negative mothers.

III. Short Answers (2 Marks Each)

1. Apoptosis

Programmed cell death.
Energy-dependent.
No inflammation.
Important in embryogenesis and tissue homeostasis.

2. Functions of Aldosterone

Increases sodium reabsorption.
Increases water retention.
Increases potassium excretion.
Increases hydrogen ion secretion.

3. Megaloblastic Anaemia

Caused by Vitamin B₁₂ or folic acid deficiency.
Characterized by large RBCs (macrocytes).
DNA synthesis is impaired.

4. Filtration Fraction

Definition:
Fraction of renal plasma flow filtered through glomeruli.

Formula:
[
\text{Filtration Fraction} = \frac{\text{GFR}}{\text{Renal Plasma Flow}}
]

Normal value: ≈ 20% (0.20)

5. Gigantism

Excess growth hormone secretion before epiphyseal closure.
Causes excessive linear growth.
Usually due to pituitary adenoma.

6. Atonic Bladder

Loss of bladder muscle tone.
Due to sensory nerve damage.
Results in urinary retention and overflow incontinence.

7. Absorption of Carbohydrates

Occurs mainly in the small intestine.
Glucose and galactose: SGLT-1 (Na⁺-dependent)
Fructose: GLUT-5
Exit into blood via GLUT-2

8. Mast Cells

Connective tissue cells containing histamine and heparin.
Involved in allergic reactions.
Activated by IgE-mediated mechanisms.

9. Milk Let-Down Reflex

Stimulus: Infant suckling.
Oxytocin released from posterior pituitary.
Myoepithelial cells contract.
Milk is ejected from alveoli into ducts.

10. Shape of Erythrocytes

Biconcave, non-nucleated discs.
Diameter: 7–8 μm
Thickness: 2.5 μm at edge, 1 μm at center
Shape increases surface area and flexibility.

These answers correspond to the questions listed in the uploaded MBBS First Year Physiology including Biophysics I (August 2019) examination paper.

MBBS First Year – Physiology including Biophysics II (August 2019)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Describe the optic pathway from the photoreceptors to the visual cortex. Add a note on visual field defects produced by lesions at various levels of the pathway.

Introduction

The optic pathway transmits visual impulses from the retina to the visual cortex in the occipital lobe, enabling perception of vision.

Optic Pathway

1. Retina

Visual impulses begin in the:

Rods (dim vision)
Cones (color and daylight vision)

The pathway within the retina is:

Photoreceptors → Bipolar cells → Ganglion cells

The axons of ganglion cells form the optic nerve.

2. Optic Nerve

One optic nerve arises from each eye.
Passes through the optic canal to reach the cranial cavity.

3. Optic Chiasma

Nasal retinal fibres cross to the opposite side.
Temporal retinal fibres remain uncrossed.

4. Optic Tract

Each optic tract carries fibres from:

Ipsilateral temporal retina
Contralateral nasal retina

Thus, each tract carries information from the opposite visual field.

5. Lateral Geniculate Body (LGB)

Main relay nucleus in the thalamus.
Synapse occurs between optic tract fibres and third-order neurons.

6. Optic Radiation (Geniculocalcarine Tract)

Fibres pass through:

Internal capsule
Temporal lobe (Meyer’s loop)
Parietal lobe

Terminate in the visual cortex.

7. Visual Cortex

Located in:

Area 17 (Primary visual cortex)
Around the calcarine sulcus of the occipital lobe.

Visual association areas (Areas 18 and 19) interpret the visual information.

Visual Field Defects

Site of Lesion	Defect Produced
Optic nerve	Ipsilateral monocular blindness
Central optic chiasma	Bitemporal hemianopia
Lateral optic chiasma	Ipsilateral nasal hemianopia
Optic tract	Contralateral homonymous hemianopia
Meyer’s loop (Temporal lobe)	Contralateral superior quadrantanopia (“Pie in the sky”)
Parietal optic radiation	Contralateral inferior quadrantanopia
Primary visual cortex	Contralateral homonymous hemianopia with macular sparing

Applied Anatomy

Pituitary tumors compress the optic chiasma causing bitemporal hemianopia.
Stroke involving optic radiation produces quadrantanopia.
Occipital lobe infarction causes homonymous hemianopia with macular sparing.

II. Write Notes (4 Marks Each)

1. Brown–Séquard Syndrome

Definition

Hemisection of one half of the spinal cord.

Causes

Trauma
Tumors
Spinal cord injury

Features

Ipsilateral

Spastic paralysis below lesion
Loss of proprioception
Loss of vibration sense

Contralateral

Loss of pain and temperature sensation beginning 1–2 segments below the lesion.

2. Histotoxic Hypoxia

Definition

Cells cannot utilize oxygen despite adequate oxygen delivery.

Causes

Cyanide poisoning
Hydrogen sulfide poisoning

Features

High venous oxygen content
Normal arterial oxygen tension
Cellular respiration inhibited

Treatment

Hydroxocobalamin
Sodium thiosulfate

3. Physiology of Fetal Circulation Before and After Birth

Before Birth

Special shunts:

Ductus venosus
Foramen ovale
Ductus arteriosus

Placenta functions as the organ of gas exchange.

After Birth

Umbilical cord is clamped.
Lungs expand.
Pulmonary vascular resistance decreases.
Foramen ovale closes.
Ductus arteriosus closes.
Ductus venosus closes.

Adult circulation is established.

4. Special Features of Coronary Circulation

Coronary blood flow occurs mainly during diastole.
High oxygen extraction (≈70–80%).
Increased demand met by increased blood flow.
Rich autoregulation.
Controlled by metabolic factors (adenosine, nitric oxide).

Clinical importance:

Coronary artery disease
Myocardial infarction

5. Caisson’s Disease

Definition

Decompression sickness caused by rapid ascent from high-pressure environments.

Cause

Nitrogen bubbles form in blood and tissues.

Symptoms

Joint pain (“Bends”)
Breathlessness (“Chokes”)
Paralysis
Neurological symptoms

Prevention

Slow decompression.

Treatment

Hyperbaric oxygen therapy.

III. Short Answers (2 Marks Each)

1. Implicit Memory

Unconscious memory.
Includes procedural skills and habits.
Involves basal ganglia and cerebellum.

2. Stages of Sleep Cycle

NREM Sleep

Stage N1
Stage N2
Stage N3 (slow-wave sleep)

REM Sleep

Rapid eye movements
Dreaming
Muscle atonia

3. Denervation Hypersensitivity

Increased sensitivity of a denervated organ to neurotransmitters.
Due to increased receptor expression after loss of nerve supply.

4. Determinants of Force of Contraction of Heart

Preload
Afterload
Myocardial contractility
Heart rate

5. Bohr Effect

Increased CO₂ or decreased pH reduces the affinity of hemoglobin for oxygen.
Facilitates oxygen unloading to tissues.

6. Jugular Venous Pulse (JVP)

Components:

a wave
c wave
x descent
v wave
y descent

Reflects right atrial pressure.

7. Endogenous Opioids

Examples:

Endorphins
Enkephalins
Dynorphins

Functions:

Pain modulation
Stress response
Mood regulation

8. Mouth-to-Mouth Respiration

Rescue breathing technique.
Used during cardiopulmonary resuscitation (CPR).
Delivers expired air containing approximately 16–17% oxygen.

9. Heart Block

Definition:
Impaired conduction of impulses through the atrioventricular (AV) node or His-Purkinje system.

Types:

First-degree AV block
Second-degree AV block
Third-degree (complete) AV block

10. Respiratory Distress Syndrome of Newborn

Cause

Deficiency of pulmonary surfactant in premature infants.

Features

Tachypnea
Cyanosis
Chest retractions
Hypoxemia

Prevention/Treatment

Antenatal corticosteroids
Exogenous surfactant therapy
Oxygen and ventilatory support

These answers correspond to the questions listed in the uploaded MBBS First Year Physiology including Biophysics II (August 2019) examination paper.

MBBS First Year – Biochemistry I (August 2019)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Explain the glycogen metabolism and its regulation. Add a note on associated disorders.

Introduction

Glycogen is the storage form of glucose in animals. It is mainly stored in the liver (maintains blood glucose) and skeletal muscle (provides energy for muscle contraction). Glycogen metabolism includes glycogenesis (synthesis) and glycogenolysis (breakdown).

A. Glycogenesis (Synthesis of Glycogen)

Site

Liver
Skeletal muscle

Steps

Glucose → Glucose-6-phosphate
- Enzyme: Hexokinase (muscle) / Glucokinase (liver)
Glucose-6-phosphate → Glucose-1-phosphate
- Enzyme: Phosphoglucomutase
Glucose-1-phosphate + UTP → UDP-glucose
- Enzyme: UDP-glucose pyrophosphorylase
Formation of Glycogen Primer
- Protein: Glycogenin
Chain Elongation
- Enzyme: Glycogen synthase
- Forms α-1,4 glycosidic bonds
Branch Formation
- Enzyme: Branching enzyme (amylo-1,4 → 1,6 transglycosylase)
- Forms α-1,6 glycosidic bonds

B. Glycogenolysis (Breakdown of Glycogen)

Steps

Glycogen → Glucose-1-phosphate
- Enzyme: Glycogen phosphorylase
Debranching
- Transferase activity
- α-1,6 glucosidase activity
Glucose-1-phosphate → Glucose-6-phosphate
- Enzyme: Phosphoglucomutase
In Liver
- Glucose-6-phosphatase converts G6P to free glucose.
In Muscle
- G6P enters glycolysis (muscle lacks glucose-6-phosphatase).

Regulation of Glycogen Metabolism

Hormonal Regulation

Insulin

Stimulates glycogenesis
Activates glycogen synthase
Inhibits glycogen phosphorylase

Glucagon

Acts mainly on liver
Stimulates glycogenolysis
Inhibits glycogenesis

Adrenaline (Epinephrine)

Stimulates glycogen breakdown in liver and muscle
Acts through cAMP pathway

Allosteric Regulation

Glucose-6-phosphate activates glycogen synthase.
AMP activates glycogen phosphorylase in muscle.
ATP and glucose-6-phosphate inhibit glycogen phosphorylase.

Associated Disorders (Glycogen Storage Diseases)

Disease	Enzyme Deficiency	Features
Type I (Von Gierke)	Glucose-6-phosphatase	Severe fasting hypoglycemia, hepatomegaly
Type II (Pompe)	Lysosomal acid maltase	Cardiomegaly, muscle weakness
Type III (Cori)	Debranching enzyme	Hepatomegaly, mild hypoglycemia
Type V (McArdle)	Muscle glycogen phosphorylase	Exercise intolerance, muscle cramps

Importance

Maintains blood glucose during fasting.
Provides rapid energy during exercise.
Prevents hypoglycemia.

II. Write Notes (4 Marks Each)

1. Lactic Acidosis

Definition

Accumulation of lactic acid causing metabolic acidosis.

Causes

Tissue hypoxia
Shock
Sepsis
Vigorous exercise
Metformin toxicity
Liver disease

Features

Low blood pH
Elevated serum lactate
Hyperventilation
Confusion

Treatment

Correct underlying cause
Oxygen therapy
Intravenous fluids
Bicarbonate (selected cases)

2. Why Vitamin B₁₂ Deficiency Causes Macrocytic Anaemia

Vitamin B₁₂ is required for DNA synthesis.
Deficiency impairs thymidine synthesis.
Nuclear maturation is delayed while cytoplasmic growth continues.
Produces large immature red cells (megaloblasts).
Results in macrocytic (megaloblastic) anaemia.
Neurological manifestations may also occur.

3. Distribution of Dietary Lipids After Digestion and Absorption

Dietary lipids are emulsified by bile salts.
Digested by pancreatic lipase.
Absorbed by intestinal mucosal cells.
Re-esterified to triglycerides.
Packaged into chylomicrons.
Enter lymphatics (lacteals).
Reach blood via thoracic duct.
Lipoprotein lipase releases fatty acids to tissues.
Chylomicron remnants are taken up by the liver.

4. Phospholipids

Definition

Complex lipids containing phosphate.

Types

Phosphatidylcholine (Lecithin)
Phosphatidylethanolamine
Phosphatidylserine
Phosphatidylinositol
Cardiolipin
Sphingomyelin

Functions

Cell membrane structure
Lung surfactant (DPPC)
Lipoprotein formation
Cell signaling
Myelin sheath formation

5. Glucose Transporters Relevant to Insulin Secretion and Action

Transporter	Site	Function
GLUT-1	RBC, Brain	Basal glucose uptake
GLUT-2	Liver, Pancreatic β-cells	Glucose sensing and insulin secretion
GLUT-3	Brain	High-affinity glucose transport
GLUT-4	Skeletal muscle, Adipose tissue	Insulin-dependent glucose uptake
GLUT-5	Intestine	Fructose transport

III. Short Answers (2 Marks Each)

1. Importance of HbA1c Testing

Reflects average blood glucose over the previous 2–3 months.
Used for diagnosis and monitoring of diabetes mellitus.
Helps assess long-term glycaemic control.

2. Wernicke–Korsakoff Syndrome

Due to thiamine (Vitamin B₁) deficiency, commonly in chronic alcoholism.
Wernicke encephalopathy: confusion, ataxia, ophthalmoplegia.
Korsakoff syndrome: memory loss and confabulation.

3. Effect of Non-Competitive Inhibition on Km and Vmax

Km: Unchanged.
Vmax: Decreased.

4. Schematic Representation of Electron Transport Chain

NADH
  │
Complex I
  │
Coenzyme Q
  │
Complex III
  │
Cytochrome c
  │
Complex IV
  │
O₂ → H₂O

FADH₂ enters at Complex II → Coenzyme Q

ATP is synthesized by Complex V (ATP synthase).

5. Carnitine Transport

Long-chain fatty acids are transported into mitochondria by the carnitine shuttle.
Enzymes:
- CPT-I
- Carnitine–acylcarnitine translocase
- CPT-II
Required for β-oxidation of long-chain fatty acids.

6. Vitamin K Cycle

Vitamin K is reduced to its active hydroquinone form.
Acts as a cofactor for γ-carboxylation of clotting factors II, VII, IX and X.
Oxidized vitamin K is recycled by vitamin K epoxide reductase (VKOR).
Warfarin inhibits VKOR.

7. Metabolic Basis of Aspirin as an Anti-Platelet Agent

Aspirin irreversibly inhibits cyclooxygenase-1 (COX-1).
Decreases thromboxane A₂ synthesis.
Prevents platelet aggregation.
Effect lasts for the lifespan of the platelet (7–10 days).

8. Interpretation of the Following Conditions

a) Elevated Alkaline Phosphatase (ALP)

Cholestatic liver disease
Bone disorders (e.g., Paget disease, rickets, osteomalacia, healing fractures)

b) Elevated Acid Phosphatase (ACP)

Carcinoma of the prostate (classically)
Prostatic diseases
Increased osteoclastic activity

9. Proteasome

Large intracellular protein complex.
Degrades ubiquitin-tagged proteins.
Maintains protein quality control and regulates the cell cycle.

10. How Do Enzymes Reduce the Activation Energy of a Reaction?

Stabilize the transition state.
Bring substrates into close proximity.
Provide a favorable microenvironment.
Form temporary enzyme–substrate complexes.
Lower activation energy without changing the overall free energy (ΔG) of the reaction.

These answers correspond to the questions listed in the uploaded MBBS First Year Biochemistry I (August 2019) examination paper.

MBBS First Year – Biochemistry II (August 2019)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Explain the biochemical basis of clinical features of porphyrias.

Introduction

Porphyrias are a group of inherited or acquired disorders caused by deficiencies of enzymes involved in heme biosynthesis. Defective heme synthesis leads to accumulation of porphyrin precursors or porphyrins, producing characteristic clinical manifestations.

Heme Biosynthesis (Outline)

Site: Liver and bone marrow.

Steps

Glycine + Succinyl-CoA → δ-Aminolevulinic acid (ALA)
- Enzyme: ALA synthase (rate-limiting; requires vitamin B₆)
ALA → Porphobilinogen
Porphobilinogen → Hydroxymethylbilane
→ Uroporphyrinogen III
→ Coproporphyrinogen III
→ Protoporphyrin IX
Protoporphyrin IX + Fe²⁺ → Heme
- Enzyme: Ferrochelatase

Biochemical Basis of Clinical Features

1. Acute Neurovisceral Manifestations

Seen in Acute Intermittent Porphyria (AIP).
Deficiency: Porphobilinogen deaminase.
Accumulation of ALA and porphobilinogen (PBG).
Neurotoxicity causes:
- Severe abdominal pain
- Vomiting
- Peripheral neuropathy
- Muscle weakness
- Psychiatric symptoms
- Seizures

2. Photosensitivity

Due to accumulation of porphyrins in the skin.
Porphyrins absorb ultraviolet light and generate reactive oxygen species.
Clinical features:
- Photosensitivity
- Blistering
- Hyperpigmentation
- Scarring
- Hypertrichosis

3. Reddish Urine

Excess porphyrins and porphobilinogen are excreted in urine.
Urine may become dark red or port-wine colored on standing.

4. Liver Involvement

Common in Porphyria Cutanea Tarda (PCT).
Associated with:
- Hepatitis C
- Alcohol abuse
- Iron overload

Types of Porphyrias

Type	Enzyme Deficiency	Main Features
Acute Intermittent Porphyria	Porphobilinogen deaminase	Abdominal pain, neuropathy, psychiatric symptoms
Porphyria Cutanea Tarda	Uroporphyrinogen decarboxylase	Photosensitivity, blistering
Congenital Erythropoietic Porphyria	Uroporphyrinogen III synthase	Severe photosensitivity, hemolysis
Erythropoietic Protoporphyria	Ferrochelatase	Photosensitivity

Diagnosis

Urinary ALA and PBG
Urine porphyrin analysis
Plasma and fecal porphyrins
Enzyme assays
Genetic testing

Treatment

Avoid precipitating factors (alcohol, certain drugs, fasting).
Intravenous hemin for acute attacks.
High-carbohydrate intake/glucose infusion.
Sun protection for photosensitive forms.
Phlebotomy or low-dose hydroxychloroquine in Porphyria Cutanea Tarda.

Conclusion

Porphyrias result from enzyme defects in heme synthesis, causing accumulation of toxic intermediates that produce neurovisceral symptoms, photosensitivity, and pigmentary changes.

II. Write Notes (4 Marks Each)

1. Mutation

Definition

A mutation is a permanent heritable change in the DNA sequence.

Types

Point mutation
Missense mutation
Nonsense mutation
Silent mutation
Frameshift mutation
Insertion
Deletion

Causes

Spontaneous errors
Radiation
Chemicals
Viruses

Significance

Genetic diseases
Cancer
Evolution
Drug resistance

2. Types, Properties and Functions of Immunoglobulins

Class	Main Property	Function
IgG	Most abundant; crosses placenta	Secondary immune response, opsonization
IgA	Secretory antibody	Mucosal immunity
IgM	First antibody produced	Primary immune response, complement activation
IgE	Binds mast cells	Allergy and parasitic infections
IgD	B-cell surface receptor	B-cell activation

3. Congenital Jaundice

Definition

Jaundice due to inherited defects in bilirubin metabolism.

Types

Gilbert syndrome: mild decrease in UDP-glucuronyl transferase activity.
Crigler–Najjar syndrome: severe deficiency/absence of UDP-glucuronyl transferase.
Dubin–Johnson syndrome: impaired conjugated bilirubin excretion.
Rotor syndrome: defect in hepatic bilirubin storage.

4. Genomic Library

Definition

A genomic library is a collection of cloned DNA fragments representing the entire genome of an organism.

Preparation

DNA extraction
Restriction enzyme digestion
Insertion into vectors
Transformation into host cells

Applications

Gene identification
Genome mapping
DNA sequencing
Recombinant DNA technology

5. Products Formed from Tryptophan

Niacin (Vitamin B₃)
Serotonin
Melatonin
Alanine
Acetyl-CoA
CO₂

III. Short Answers (2 Marks Each)

1. Tests to Assess Biosynthetic Function of Liver

Serum albumin
Prothrombin time (PT/INR)
Serum fibrinogen
Clotting factor levels
Serum cholesterol (supportive)

2. Splicing of hnRNA

Removal of introns from heterogeneous nuclear RNA (hnRNA).
Exons are joined by the spliceosome.
Produces mature mRNA for translation.

3. Normal Reference Values

Parameter	Normal Value
Serum Creatinine	0.6–1.2 mg/dL
Serum Potassium	3.5–5.0 mmol/L
TSH	0.4–4.0 mIU/L
Blood pH	7.35–7.45

4. Compare Promoter with Enhancer

Promoter	Enhancer
Located near gene	Can be far from gene
Initiates transcription	Increases transcription rate
Essential for transcription	Modulates transcription efficiency
Binds RNA polymerase and transcription factors	Binds activator proteins

5. Role of Antidiuretic Hormone (ADH) in Regulation of Osmolality

Secreted from the posterior pituitary.
Increases water reabsorption in collecting ducts by inserting aquaporin-2 channels.
Reduces plasma osmolality and concentrates urine.

6. Role of Different Types of RNA in Protein Synthesis

mRNA: carries genetic code from DNA to ribosomes.
tRNA: transports amino acids to ribosomes.
rRNA: structural and catalytic component of ribosomes.

7. Interpretation of Hemoglobin Electrophoresis

Finding: Elevated HbF and HbA₂ with absence of HbA in a 2-year-old child with severe anemia.

Interpretation: β-Thalassemia major (Cooley’s anemia).

8. Four Conditions with Reversed Albumin : Globulin Ratio

Condition	Reason
Cirrhosis of liver	Decreased albumin synthesis and increased globulins
Chronic infections	Increased immunoglobulin production
Multiple myeloma	Monoclonal immunoglobulin excess
Autoimmune diseases	Increased globulin production

9. Laboratory Tests for Adrenal Hypofunction and Hyperfunction

Adrenal Hypofunction

Serum cortisol
Plasma ACTH
ACTH stimulation test
Serum electrolytes (hyponatremia, hyperkalemia)

Adrenal Hyperfunction

Serum cortisol
24-hour urinary free cortisol
Dexamethasone suppression test
Plasma catecholamines/metanephrines (for pheochromocytoma)

10. Two Examples of Xenobiotic Metabolism Acting on Endogenous Substances

Metabolism of bilirubin (glucuronidation)
Metabolism of steroid hormones (hydroxylation and conjugation)

These answers correspond to the questions listed in the uploaded MBBS First Year Biochemistry II (August 2019) examination paper.

MBBS First Year – Anatomy I (August 2020)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions. The page image shows the following questions.

I. Essay (10 Marks)

1. Write in detail about the Femoral artery and its relations and applied anatomy. Add a note on femoral sheath, femoral canal and femoral ring.

Femoral Artery

Definition

The femoral artery is the continuation of the external iliac artery beyond the mid-inguinal point. It is the chief arterial supply of the lower limb.

Extent

Begins: Behind the mid-inguinal point.
Ends: At the adductor hiatus, where it continues as the popliteal artery.

Course

Passes through the femoral triangle.
Descends in the adductor canal.
Enters the popliteal fossa through the adductor hiatus.

Relations

In the Femoral Triangle

Anterior

Skin
Superficial fascia
Fascia lata
Femoral sheath

Posterior

Psoas major tendon
Pectineus
Adductor longus

Medial

Femoral vein (upper part)

Lateral

Femoral nerve

Branches

Superficial epigastric artery
Superficial circumflex iliac artery
Superficial external pudendal artery
Deep external pudendal artery
Profunda femoris artery
Descending genicular artery
Muscular branches

Femoral Sheath

Definition
A funnel-shaped fascial sleeve enclosing the proximal femoral vessels.

Formation

Anterior wall: Transversalis fascia
Posterior wall: Iliac fascia

Compartments

Lateral – Femoral artery
Intermediate – Femoral vein
Medial – Femoral canal

Femoral Canal

Medial compartment of the femoral sheath.
About 1.25 cm long.
Contains:
- Fat
- Lymphatics
- Deep inguinal lymph node (Cloquet’s node)

Femoral Ring

Boundaries

Anterior: Inguinal ligament
Posterior: Pectineal ligament
Medial: Lacunar ligament
Lateral: Femoral vein

Applied Anatomy

Femoral pulse is palpated at the mid-inguinal point.
Common site for arterial catheterization and coronary angiography.
Femoral artery compression controls lower limb hemorrhage.
Femoral aneurysm.
Femoral hernia passes through the femoral ring and canal; more common in females and prone to strangulation.

II. Write Notes (4 Marks Each)

1. Microscopic Structure of Hyaline Cartilage

Features

Covered by perichondrium (except articular cartilage).
Chondrocytes lie in lacunae.
Homogeneous extracellular matrix rich in type II collagen and proteoglycans.
Avascular; nourished by diffusion.

Functions

Provides smooth articular surface.
Supports respiratory passages.
Forms fetal skeleton.

2. Lymphatic Drainage of Mammary Gland

Drainage

About 75% drains to axillary lymph nodes (mainly anterior/pectoral group).
Medial part drains to parasternal (internal thoracic) nodes.
Some lymph drains to posterior intercostal and supraclavicular nodes.
Lymphatic communication exists with the opposite breast.

Applied Anatomy

Route of spread of carcinoma breast.
Sentinel lymph node biopsy is important in staging.

3. Intertubercular (Bicipital) Sulcus of Humerus

Boundaries

Lateral lip: Greater tubercle
Medial lip: Lesser tubercle
Floor: Shaft of humerus

Tendon of long head of biceps brachii.
Ascending branch of anterior circumflex humeral artery.

Muscle Attachments

Lateral lip: Pectoralis major
Floor: Latissimus dorsi
Medial lip: Teres major

4. Inguinal Canal

Extent

Deep inguinal ring to superficial inguinal ring.

Walls

Anterior: External oblique aponeurosis
Posterior: Transversalis fascia
Roof: Internal oblique and transversus abdominis
Floor: Inguinal ligament

Male

Spermatic cord
Genital branch of genitofemoral nerve

Female

Round ligament of uterus
Genital branch of genitofemoral nerve

Applied Anatomy

Direct and indirect inguinal hernia.

5. Facial Vein

Formation

Continuation of the angular vein at the medial angle of the eye.

Course

Descends across the face.
Crosses the lower border of the mandible.
Joins the anterior division of the retromandibular vein to form the common facial vein.

Termination

Drains into the internal jugular vein.

Applied Anatomy

Facial vein communicates with the cavernous sinus through the ophthalmic veins, allowing spread of infection from the “dangerous area” of the face.

III. Short Answers (2 Marks Each)

1. Parts of Ureter

Abdominal part
Pelvic part
Intramural (intravesical) part

2. Sesamoid Bone

Bone embedded within a tendon.
Reduces friction and alters the direction of muscle pull.
Example: Patella.

3. Sustentaculum Tali

Medial projection of the calcaneus.
Supports the talus.
Attachment for the spring ligament.
Groove below transmits the flexor hallucis longus tendon.

4. Caput Medusae

Dilated superficial veins radiating from the umbilicus.
Caused by portal hypertension due to recanalization of paraumbilical veins.

5. Popliteal Fossa

Boundaries

Superolateral: Biceps femoris
Superomedial: Semimembranosus and semitendinosus
Inferolateral: Lateral head of gastrocnemius and plantaris
Inferomedial: Medial head of gastrocnemius

Contents

Tibial nerve
Common fibular nerve
Popliteal vein
Popliteal artery
Popliteal lymph nodes

6. Dorsalis Pedis Artery

Continuation of the anterior tibial artery.
Begins anterior to the ankle joint.
Ends as the deep plantar artery.
Clinically used to assess peripheral arterial circulation.

7. Structures Piercing Cribriform Fascia

Great saphenous vein
Superficial epigastric vessels
Superficial circumflex iliac vessels
Superficial external pudendal vessels
Lymphatics

8. Supratrochlear Lymph Nodes

Located above the medial epicondyle of the humerus.
Drain the medial side of the hand, forearm, and middle finger.
Drain into the lateral axillary lymph nodes.

9. Contents of Carotid Sheath

Common/internal carotid artery
Internal jugular vein
Vagus nerve
Deep cervical lymph nodes
Carotid sympathetic plexus

10. Course of Lower Oesophagus

Enters the abdomen through the oesophageal hiatus (T10).
Passes downward and to the left for about 1–2 cm.
Ends at the cardiac orifice of the stomach (approximately T11 vertebral level).
Supplied by the left gastric artery and drained by the left gastric vein, forming an important portosystemic anastomosis.

These answers are based on the questions visible in the uploaded MBBS First Year Anatomy I (August 2020) examination paper.

MBBS First Year – Anatomy II (August 2020)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions. The questions visible in the uploaded paper are used below.

I. Essay (10 Marks)

1. Write in detail about the Thyroid gland under the following headings:

Situation, lobes, coverings, relations, blood supply. Add a note on applied anatomy.

Thyroid Gland

Definition

The thyroid gland is the largest endocrine gland. It is highly vascular and lies in the anterior part of the neck, opposite the C5–T1 vertebrae.

Situation

Lies in front of the lower part of the larynx and upper trachea.
Extends from the oblique line of the thyroid cartilage to the 5th–6th tracheal rings.

Parts (Lobes)

Right lobe
Left lobe
Isthmus (joins both lobes)
Pyramidal lobe (present in about 50% of individuals)

Coverings

True capsule – fibrous capsule closely adherent to the gland.
False capsule – derived from the pretracheal layer of deep cervical fascia.

Relations

Lateral Surface

Sternohyoid
Sternothyroid
Superior belly of omohyoid
Sternocleidomastoid

Medial Surface

Larynx
Trachea
Pharynx
Oesophagus (especially left lobe)
Cricothyroid muscle
Inferior constrictor
Recurrent laryngeal nerve

Posterior Border

Superior parathyroid gland
Inferior parathyroid gland
Inferior thyroid artery

Blood Supply

Arterial Supply

Superior thyroid artery (external carotid artery)
Inferior thyroid artery (thyrocervical trunk)
Thyroid ima artery (occasionally)

Venous Drainage

Superior thyroid vein → Internal jugular vein
Middle thyroid vein → Internal jugular vein
Inferior thyroid vein → Brachiocephalic vein

Lymphatic Drainage

Prelaryngeal nodes
Pretracheal nodes
Paratracheal nodes
Deep cervical lymph nodes

Nerve Supply

Sympathetic fibers from cervical sympathetic ganglia (vasomotor).
Hormone secretion is regulated by TSH, not by direct nerve supply.

Applied Anatomy

Goitre
Hyperthyroidism (Graves disease)
Hypothyroidism
Thyroidectomy
Injury to recurrent laryngeal nerve causing hoarseness of voice
Accidental removal of parathyroid glands causing hypocalcaemia

II. Write Notes (4 Marks Each)

1. Sinuses of Pericardium

Types

Transverse sinus
Oblique sinus

Transverse Sinus

Lies between ascending aorta and pulmonary trunk (anteriorly) and superior vena cava (posteriorly).
Used by cardiac surgeons to clamp the great arteries.

Oblique Sinus

Blind recess behind the left atrium.
Formed by reflection of serous pericardium around pulmonary veins and inferior vena cava.

2. Nasal Septum

Parts

Bony Part

Perpendicular plate of ethmoid
Vomer
Nasal crest of maxilla
Nasal crest of palatine bone

Cartilaginous Part

Septal cartilage

Blood Supply

Sphenopalatine artery
Greater palatine artery
Superior labial artery
Anterior and posterior ethmoidal arteries

Applied Anatomy

Deviated nasal septum (DNS)
Epistaxis from Little’s area

3. Cerebellar Peduncles

Superior Cerebellar Peduncle

Connects cerebellum with midbrain.
Mainly efferent fibers.

Middle Cerebellar Peduncle

Connects cerebellum with pons.
Largest peduncle.
Contains pontocerebellar fibers.

Inferior Cerebellar Peduncle

Connects cerebellum with medulla.
Carries mainly afferent fibers.

Functions

Coordination of voluntary movements
Maintenance of posture and balance

4. Histology of Cornea

Layers (from anterior to posterior):

Corneal epithelium
Bowman’s membrane
Stroma (substantia propria)
Descemet’s membrane
Endothelium

Features

Transparent
Avascular
Rich sensory nerve supply
Nourished by tears and aqueous humor

5. Hyoglossus Muscle

Origin

Greater horn and body of hyoid bone

Insertion

Side of tongue

Nerve Supply

Hypoglossal nerve (CN XII)

Action

Depresses and retracts the tongue.

Relations

Superficial

Lingual nerve
Hypoglossal nerve
Submandibular duct

Deep

Glossopharyngeal nerve
Stylohyoid ligament

III. Short Answers (2 Marks Each)

1. Fallot’s Tetralogy

Four congenital cardiac defects:

Pulmonary stenosis
Ventricular septal defect (VSD)
Overriding aorta
Right ventricular hypertrophy

2. Pleural Recesses

Costodiaphragmatic recess
Costomediastinal recess

Clinical importance:

Site for pleural fluid accumulation.
Thoracocentesis is commonly performed through the costodiaphragmatic recess.

3. Corpus Callosum

Largest commissural fiber bundle.
Connects the two cerebral hemispheres.
Parts: Rostrum, genu, body, splenium.

4. Auditory (Pharyngotympanic/Eustachian) Tube

Connects the middle ear to the nasopharynx.
Length: About 36 mm.
Functions:
- Equalizes middle ear pressure.
- Drains middle ear secretions.

5. Ligamentum Arteriosum

Fibrous remnant of the fetal ductus arteriosus.
Connects the pulmonary trunk to the arch of the aorta.
Related to the left recurrent laryngeal nerve.

6. Peritonsillar (Paratonsillar) Abscess

Collection of pus around the palatine tonsil (Quinsy).
Features:
- Severe sore throat
- Dysphagia
- Fever
- Trismus
- Muffled “hot potato” voice

7. Weber’s Syndrome

Midbrain lesion involving the cerebral peduncle and oculomotor nerve.
Features:
- Ipsilateral oculomotor nerve palsy
- Contralateral hemiplegia

8. Ciliary Ganglion

Parasympathetic ganglion in the orbit.
Located between the optic nerve and lateral rectus muscle.
Receives:
- Parasympathetic root (oculomotor nerve)
- Sympathetic root
- Sensory root (nasociliary nerve)
Supplies the sphincter pupillae and ciliary muscle through the short ciliary nerves.

9. Tendon of Todaro

Fibrous band extending from the valve of the inferior vena cava (Eustachian valve) to the central fibrous body.
Forms one boundary of the Triangle of Koch, where the AV node is located.

10. Reticular Formation

Diffuse network of neurons in the brainstem.
Functions:
- Maintains consciousness (ascending reticular activating system)
- Regulates sleep–wake cycle
- Controls autonomic functions
- Modulates pain
- Influences muscle tone and posture

These answers are based on the questions shown in the uploaded MBBS First Year Anatomy II (August 2020) examination paper.

MBBS First Year – Physiology including Biophysics I (August 2020)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions. The questions visible in the uploaded page are answered below.

I. Essay (10 Marks)

1. Describe in detail the mechanism of clotting of blood. Add a note on Disorders.

Introduction

Blood clotting (coagulation) is the process by which blood changes from a liquid to a gel, preventing excessive blood loss after vascular injury. It involves a series of enzymatic reactions known as the coagulation cascade.

Stages of Blood Coagulation

Stage 1: Formation of Prothrombin Activator

A. Extrinsic Pathway (Rapid)

Initiated by tissue injury.
Tissue factor (Factor III) is released.
Tissue factor combines with Factor VII in the presence of calcium.
Activates Factor X.

B. Intrinsic Pathway (Slow)

Initiated by contact of blood with exposed collagen.
Sequential activation:
- Factor XII → XI → IX
- Factor IX + Factor VIII + platelet phospholipid + calcium activate Factor X.

Common Pathway

Activated Factor X combines with Factor V, calcium and platelet phospholipid to form prothrombin activator.
Prothrombin (Factor II) → Thrombin.
Thrombin converts Fibrinogen (Factor I) into Fibrin.
Factor XIII stabilizes fibrin by cross-linking.
Stable fibrin clot is formed.

Clot Retraction

Platelets contract through actin and myosin.
Serum is squeezed out.
Wound edges are approximated.

Fibrinolysis

Plasminogen is converted to plasmin by tissue plasminogen activator (tPA).
Plasmin digests fibrin and dissolves the clot.

Disorders of Blood Clotting

Bleeding Disorders

Hemophilia A – Factor VIII deficiency
Hemophilia B (Christmas disease) – Factor IX deficiency
Von Willebrand disease
Vitamin K deficiency
Liver disease
Thrombocytopenia

Thrombotic Disorders

Deep vein thrombosis (DVT)
Pulmonary embolism
Disseminated intravascular coagulation (DIC)

Anticoagulants

Heparin
Warfarin
Direct oral anticoagulants (DOACs)

Laboratory Tests

Bleeding time (BT)
Clotting time (CT)
Prothrombin time (PT/INR)
Activated partial thromboplastin time (APTT)

II. Write Notes (4 Marks Each)

1. Factors Affecting Glomerular Filtration Rate (GFR)

Definition: GFR is the volume of filtrate formed by both kidneys per minute (Normal: 125 mL/min).

Factors

Glomerular hydrostatic pressure (↑ GFR)
Plasma colloid osmotic pressure (↓ GFR)
Bowman’s capsule hydrostatic pressure (↓ GFR)
Renal blood flow
Afferent and efferent arteriolar tone
Sympathetic stimulation
Autoregulation (myogenic mechanism and tubuloglomerular feedback)

2. Micturition Reflex

Stretch receptors in the bladder wall are stimulated by filling.
Afferent impulses travel via pelvic nerves to the sacral spinal cord (S2–S4).
Parasympathetic efferents cause detrusor muscle contraction and relaxation of the internal urethral sphincter.
Voluntary control is exerted through the cerebral cortex via the external urethral sphincter.

3. Functions of Growth Hormone (GH)

Stimulates body growth.
Increases protein synthesis.
Promotes bone and cartilage growth.
Increases lipolysis.
Decreases glucose uptake by tissues.
Raises blood glucose concentration (diabetogenic effect).
Acts via insulin-like growth factor-1 (IGF-1).

4. Negative Feedback Mechanism

Definition: A control mechanism in which the response opposes the initial stimulus to maintain homeostasis.

Examples

Regulation of blood glucose by insulin and glucagon.
Body temperature regulation.
Blood pressure regulation.
Thyroid hormone regulation (T₃/T₄ inhibiting TSH secretion).

5. Pupillary Reflex

Light Reflex

Light stimulates the retina.
Impulses pass through the optic nerve to the pretectal nucleus.
Bilateral activation of the Edinger–Westphal nuclei.
Parasympathetic fibers travel in the oculomotor nerve to the ciliary ganglion.
Constriction of both pupils (direct and consensual light reflex).

III. Short Answers (2 Marks Each)

1. Refractory Period

Period during which an excitable tissue cannot respond (absolute refractory period) or responds only to a stronger stimulus (relative refractory period).
Ensures one-way conduction and prevents tetanus in cardiac muscle.

2. Electrocardiography (ECG)

Graphic recording of the heart’s electrical activity.
Waves: P wave, QRS complex, T wave.
Used to diagnose arrhythmias, myocardial infarction and conduction defects.

3. Name Four Gastrointestinal Hormones

Gastrin
Secretin
Cholecystokinin (CCK)
Gastric inhibitory peptide (GIP)

4. Creatinine

End product of creatine phosphate metabolism in muscle.
Excreted by the kidneys.
Marker of glomerular filtration rate (GFR).

5. Dyspnea

Difficult or labored breathing.
Causes include asthma, COPD, heart failure, pneumonia and anemia.

6. Function of Glucagon

Increases blood glucose.
Stimulates glycogenolysis.
Stimulates gluconeogenesis.
Promotes lipolysis.

7. Hering–Breuer Inflation Reflex

Stretch receptors in the lungs are activated during excessive inflation.
Impulses travel through the vagus nerve.
Inhibits inspiration and prevents overdistension of the lungs.

8. Cell Soma

Also called the cell body (perikaryon) of a neuron.
Contains the nucleus, Nissl bodies and other organelles.
Responsible for metabolic and synthetic functions.

9. Functions of Platelets

Formation of platelet plug.
Release of clotting factors.
Clot retraction.
Maintenance of vascular integrity.
Release of growth factors for tissue repair.

10. Master Gland

Pituitary gland is known as the master gland.
It secretes trophic hormones that regulate other endocrine glands:
- TSH
- ACTH
- FSH
- LH
- GH
- Prolactin

These answers correspond to the questions visible in the uploaded MBBS First Year Physiology including Biophysics I (August 2020) examination paper.

MBBS First Year – Physiology including Biophysics II (August 2020)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Describe the neural regulation of respiration. Add a note on periodic breathing.

Introduction

Respiration is regulated by neural centers located in the brainstem (medulla and pons). These centers generate the rhythm of breathing and modify ventilation according to the body’s metabolic needs.

Neural Regulation of Respiration

1. Respiratory Centres in the Medulla

A. Dorsal Respiratory Group (DRG)

Located in the nucleus tractus solitarius (NTS).
Mainly contains inspiratory neurons.
Generates the basic rhythm of quiet breathing.
Receives sensory input from:
- Vagus nerve (X)
- Glossopharyngeal nerve (IX)
Sends impulses to the diaphragm via the phrenic nerve.

B. Ventral Respiratory Group (VRG)

Located in the ventrolateral medulla.
Contains both inspiratory and expiratory neurons.
Active during forced breathing.
Includes the Pre-Bötzinger complex, considered the respiratory rhythm generator.

2. Pontine Respiratory Centres

Pneumotaxic Centre

Located in the upper pons.
Inhibits inspiration.
Regulates respiratory rate and tidal volume.
Prevents overinflation of the lungs.

Apneustic Centre

Located in the lower pons.
Stimulates and prolongs inspiration.
Normally inhibited by the pneumotaxic centre and vagal input.

3. Higher Centres

Cerebral cortex: voluntary control of respiration (speech, breath-holding).
Hypothalamus: modifies breathing during emotions, pain, and temperature changes.
Limbic system: influences respiration during emotional states.

4. Afferent Inputs

Central Chemoreceptors

Located on the ventrolateral surface of the medulla.
Stimulated by increased PCO₂ and increased H⁺ concentration in cerebrospinal fluid.
Major regulators of ventilation.

Peripheral Chemoreceptors

Carotid bodies (glossopharyngeal nerve).
Aortic bodies (vagus nerve).
Stimulated by:
- ↓ PO₂
- ↑ PCO₂
- ↑ H⁺ concentration

Pulmonary Receptors

Stretch receptors (Hering–Breuer inflation reflex).
Irritant receptors.
Juxtacapillary (J) receptors.

Efferent Pathway

Phrenic nerve (C3–C5): diaphragm.
Intercostal nerves: intercostal muscles.
Accessory muscles during forced respiration.

Periodic Breathing

Definition

Periodic breathing is characterized by alternating periods of apnea and hyperpnea.

Types

1. Cheyne–Stokes Respiration

Gradual increase and decrease in breathing depth followed by apnea.
Causes:
- Congestive heart failure
- Stroke
- Head injury
- High altitude

2. Biot’s Breathing (Ataxic Respiration)

Irregular breathing with unpredictable periods of apnea.
Seen in medullary lesions and meningitis.

3. Kussmaul Breathing

Deep, rapid breathing.
Seen in diabetic ketoacidosis and severe metabolic acidosis.

Clinical Importance

Helps assess brainstem function.
Useful in diagnosing neurological and cardiopulmonary disorders.
Abnormal respiratory patterns indicate serious CNS pathology.

II. Write Notes (4 Marks Each)

1. Factors Affecting Cardiac Output

Cardiac Output (CO) = Heart Rate × Stroke Volume

Factors

Heart rate
Preload (venous return)
Myocardial contractility
Afterload
Sympathetic stimulation (increases CO)
Parasympathetic stimulation (decreases HR and CO)

Normal Cardiac Output: Approximately 5 L/min.

2. Pacemaker Potential

Definition

The spontaneous slow depolarization occurring in SA nodal cells that initiates the heartbeat.

Mechanism

Opening of funny (If) sodium channels
Reduced potassium efflux
Calcium influx through T-type and L-type calcium channels
Reaches threshold and generates an action potential

Significance

Determines heart rate.
SA node is the normal pacemaker of the heart.

3. ECG – Lead II

Definition

A bipolar standard limb lead.

Electrode Placement

Negative electrode: Right arm
Positive electrode: Left leg

Features

Records the electrical activity from right arm to left leg.
Commonly used for rhythm monitoring.
Shows prominent P waves.

4. Auditory Pathway

Cochlea
Spiral ganglion
Cochlear nerve
Cochlear nuclei
Superior olivary complex
Lateral lemniscus
Inferior colliculus
Medial geniculate body
Auditory radiation
Primary auditory cortex (Brodmann areas 41 and 42)

5. Functions of Cerebellum

Coordination of voluntary movements
Maintenance of posture
Maintenance of equilibrium
Regulation of muscle tone
Motor learning
Coordination of eye movements

III. Short Answers (2 Marks Each)

1. Lung Compliance

Measure of the distensibility of the lungs.
Compliance = Change in lung volume / Change in transpulmonary pressure (ΔV/ΔP).
Decreased in pulmonary fibrosis and increased in emphysema.

2. Exchange Vessels

Capillaries are the exchange vessels of the circulatory system.
They allow diffusion of oxygen, carbon dioxide, nutrients, and waste products between blood and tissues.

3. Functions of Parietal Lobe

Receives and interprets somatic sensations.
Spatial orientation.
Stereognosis (recognition of an object by touch).
Language processing (dominant hemisphere).

4. Waves of EEG

Wave	Frequency	State
Alpha	8–13 Hz	Relaxed wakefulness
Beta	13–30 Hz	Alert mental activity
Theta	4–7 Hz	Children and light sleep
Delta	0.5–4 Hz	Deep sleep

5. Referred Pain

Pain perceived at a site different from its origin.
Due to convergence of visceral and somatic afferent fibers on the same spinal neurons.
Example: Left arm pain in myocardial infarction.

6. Circadian Rhythm

Approximately 24-hour biological rhythm.
Controlled by the suprachiasmatic nucleus (SCN) of the hypothalamus.
Regulates sleep–wake cycle, hormone secretion, and body temperature.

7. Aphasia

Loss or impairment of language due to cerebral lesions.
Broca’s aphasia: non-fluent speech with preserved comprehension.
Wernicke’s aphasia: fluent but meaningless speech with impaired comprehension.

8. Klüver–Bucy Syndrome

Caused by bilateral lesions of the temporal lobes (especially the amygdala).
Features:
- Hyperorality
- Hypersexuality
- Visual agnosia
- Docility
- Hyperphagia

9. Homunculus

Somatotopic representation of the body in the cerebral cortex.
Present in the primary motor and primary somatosensory cortices.
Larger cortical areas represent regions requiring fine motor control or greater sensory discrimination (e.g., hands, lips).

10. Sensations Carried by Posterior (Dorsal) Columns

Fine (discriminative) touch
Vibration sense
Conscious proprioception
Pressure sense
Two-point discrimination
Stereognosis

These answers correspond to the questions in the uploaded MBBS First Year Physiology including Biophysics II (August 2020) examination paper.

MBBS First Year – Biochemistry I (August 2020)

Solved Question Paper

The uploaded question paper contains one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Write in detail about the Glucose Malabsorption and its applications.

Introduction

Glucose malabsorption is a disorder in which glucose and galactose are not absorbed properly from the small intestine due to a defect in the sodium-dependent glucose transporter SGLT-1. It results in severe osmotic diarrhea and dehydration, especially in infancy.

Mechanism of Normal Glucose Absorption

Dietary carbohydrates are digested to monosaccharides.
Glucose and galactose are absorbed through SGLT-1 on the apical membrane of enterocytes.
Fructose is absorbed by GLUT-5.
All monosaccharides leave enterocytes via GLUT-2 into portal blood.

Glucose-Galactose Malabsorption

Cause

Mutation in the SLC5A1 gene encoding SGLT-1.
Autosomal recessive inheritance.

Pathogenesis

Failure of glucose and galactose absorption.
Water remains in the intestinal lumen.
Osmotic diarrhea develops.
Electrolyte imbalance and dehydration occur.

Clinical Features

Severe watery diarrhea beginning soon after birth.
Dehydration.
Failure to thrive.
Weight loss.
Abdominal distension.

Diagnosis

Stool analysis (acidic stool with reducing substances).
Improvement after withdrawal of glucose and galactose.
Genetic testing.
Hydrogen breath test (selected cases).

Treatment

Elimination of glucose and galactose from the diet.
Fructose-based feeds.
Oral or intravenous rehydration.
Correction of electrolyte imbalance.

Applications

1. Oral Rehydration Therapy (ORT)

ORS uses intact SGLT-1 to absorb glucose and sodium together.
Water follows by osmosis.
Basis of WHO Oral Rehydration Solution.

2. Diabetes Mellitus

SGLT-2 inhibitors (dapagliflozin, empagliflozin, canagliflozin) reduce renal glucose reabsorption and lower blood glucose.

3. Clinical Diagnosis

Helps diagnose inherited carbohydrate malabsorption disorders.

Conclusion

Glucose malabsorption results from defective intestinal glucose transport. Understanding glucose transport has led to lifesaving oral rehydration therapy and the development of SGLT inhibitors for diabetes.

II. Write Notes (4 Marks Each)

1. Fatty Liver – Causes Including Role of Lipotropic Factors

Definition

Fatty liver (hepatic steatosis) is the excessive accumulation of triglycerides in hepatocytes.

Causes

Alcoholism
Obesity
Diabetes mellitus
Protein malnutrition
Starvation
Drugs (e.g., corticosteroids)

Lipotropic Factors

Substances that prevent fat accumulation in the liver:

Choline
Methionine
Inositol
Vitamin B₁₂
Folic acid

Functions

Promote phospholipid synthesis.
Facilitate VLDL formation.
Enhance fat transport from the liver.

2. Vitamin C

Sources

Citrus fruits
Amla
Guava
Tomatoes
Green leafy vegetables

Functions

Collagen synthesis
Antioxidant
Iron absorption
Wound healing
Immune function

Deficiency

Scurvy

Bleeding gums
Poor wound healing
Petechiae
Bone pain

3. Protein-Energy Malnutrition (PEM)

Types

Marasmus

Calorie deficiency
Severe wasting
No edema

Kwashiorkor

Protein deficiency
Edema
Fatty liver
Hair and skin changes

Prevention

Balanced diet
Adequate protein intake
Breastfeeding

4. Dyslipidaemia

Definition

Abnormal levels of plasma lipids or lipoproteins.

Types

Hypercholesterolemia
Hypertriglyceridemia
Mixed dyslipidaemia

Causes

Diabetes mellitus
Hypothyroidism
Nephrotic syndrome
Obesity

Complications

Atherosclerosis
Coronary artery disease
Pancreatitis (severe hypertriglyceridemia)

5. Prion Diseases

Definition

Neurodegenerative disorders caused by abnormal prion proteins.

Examples

Creutzfeldt–Jakob disease
Kuru
Gerstmann–Sträussler–Scheinker syndrome
Fatal familial insomnia

Features

Progressive dementia
Ataxia
Myoclonus
Spongiform degeneration

III. Short Answers (2 Marks Each)

1. Define Active Site of Enzyme

The active site is the specific region of an enzyme where the substrate binds and catalysis occurs.

2. Glycosides Found in Clinically Important Glycosides

Examples:

Digoxin
Digitoxin
Ouabain
Amygdalin

3. Name Four Functions of Bile Juice

Emulsification of fats
Absorption of fat-soluble vitamins
Neutralization of gastric acid
Excretion of bilirubin and cholesterol

4. Name the Enzymes Required for Conversion of Bilirubin

Heme oxygenase
Biliverdin reductase
UDP-glucuronyl transferase

5. Daily Requirement of Vitamin A for an Adult

Men: ~900 µg retinol equivalents/day
Women: ~700 µg retinol equivalents/day

6. Name the Defect in Menkes Disease

Defect in the ATP7A copper transport protein causing impaired copper absorption and transport.

7. Name the Enzyme Defect in Von Gierke’s Disease

Glucose-6-phosphatase deficiency.

8. Name One Role of Phosphogluconate Pathway (HMP Shunt)

Production of NADPH for reductive biosynthesis.
Production of ribose-5-phosphate for nucleotide synthesis.

9. Name Three Vitamins Involved in the PCR Complex

Coenzymes commonly involved in the Pyruvate Dehydrogenase (PDH) complex:

Vitamin B₁ (Thiamine)
Vitamin B₂ (Riboflavin)
Vitamin B₃ (Niacin)
(Lipoic acid, pantothenic acid, and CoA are also required.)

10. Name Five Vitamins Involved in PPP Complex

If the intended question refers to the Pyruvate Dehydrogenase Complex, the five vitamin-derived coenzymes are:

Thiamine (Vitamin B₁)
Riboflavin (Vitamin B₂)
Niacin (Vitamin B₃)
Pantothenic acid (Vitamin B₅)
Lipoic acid (vitamin-like cofactor)

These answers are based on the questions shown in the uploaded MBBS First Year Biochemistry I (August 2020) question paper.

MBBS First Year – Biochemistry II (August 2020)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Write in detail about the Importance, Applications and Types of Polymerase Chain Reaction (PCR).

Introduction

Polymerase Chain Reaction (PCR) is an in vitro technique used to amplify a specific DNA sequence exponentially. It was developed by Kary Mullis (1983) and is one of the most important techniques in molecular biology, medical diagnosis, and forensic science.

Principle

PCR amplifies DNA using:

Template DNA
Two primers
Thermostable DNA polymerase (Taq polymerase)
dNTPs
Buffer containing Mg²⁺

Steps of PCR

1. Denaturation (94–95°C)

Double-stranded DNA separates into single strands.

2. Annealing (50–65°C)

Primers bind to complementary DNA sequences.

3. Extension (72°C)

Taq DNA polymerase synthesizes new DNA strands.

These three steps constitute one cycle. Repeating 25–35 cycles produces millions of DNA copies.

Types of PCR

Conventional PCR
Reverse Transcriptase PCR (RT-PCR)
Real-Time (Quantitative) PCR (qPCR)
Multiplex PCR
Nested PCR
Hot-start PCR
Digital PCR

Applications

Diagnosis of infectious diseases (e.g., tuberculosis, HIV, COVID-19)
Detection of genetic disorders
Prenatal diagnosis
Cancer diagnosis and mutation analysis
Forensic DNA fingerprinting
Paternity testing
Gene cloning
DNA sequencing
Research in molecular biology

Advantages

Highly sensitive
Highly specific
Rapid
Requires only a small amount of DNA
Can detect early infections

Limitations

Risk of contamination
Requires specialized equipment
False-positive results may occur
Expensive compared with conventional methods

Conclusion

PCR is a rapid, sensitive, and specific technique that has revolutionized diagnosis, research, forensic medicine, and biotechnology.

II. Write Notes (4 Marks Each)

1. Collagen

Definition

Collagen is the most abundant structural protein in the human body.

Types

Type I – Bone, tendon, skin
Type II – Cartilage
Type III – Reticular fibers
Type IV – Basement membrane

Functions

Provides tensile strength
Wound healing
Structural support of tissues

Disorders

Scurvy
Osteogenesis imperfecta
Ehlers–Danlos syndrome

2. Acid–Base Interpretation of Blood Gas (ABG)

Normal Values

pH: 7.35–7.45
PaCO₂: 35–45 mmHg
HCO₃⁻: 22–26 mmol/L

Disorders

Respiratory acidosis
Respiratory alkalosis
Metabolic acidosis
Metabolic alkalosis

Clinical Uses

Assessment of respiratory failure
ICU monitoring
Acid–base disorders

3. Genetic Code

Properties

Triplet code
Universal
Degenerate
Non-overlapping
Commaless
Nearly universal
Unambiguous

Start Codon

AUG (Methionine)

Stop Codons

4. Clinical Features of Defect in Classical Phenylketonuria (PKU)

Intellectual disability
Developmental delay
Seizures
Fair skin and hair
Musty/mousy odor of urine
Eczema

Cause

Phenylalanine hydroxylase deficiency.

Treatment

Low-phenylalanine diet with tyrosine supplementation.

5. Cytochrome P450 (CYP450)

Functions

Drug metabolism
Steroid hormone synthesis
Detoxification of xenobiotics
Vitamin D metabolism

Clinical Importance

Drug interactions
Variable drug response due to genetic polymorphism

III. Short Answers (2 Marks Each)

1. Name Two Inborn Errors of Metabolism

Phenylketonuria (PKU)
Maple Syrup Urine Disease (MSUD)

2. Name Two Different Vitamins and Their Coenzyme Forms

Vitamin	Coenzyme
Vitamin B₁	Thiamine pyrophosphate (TPP)
Vitamin B₂	Flavin adenine dinucleotide (FAD)

3. Normal Creatinine Clearance Value in an Adult

90–120 mL/min (approximately 125 mL/min in healthy young adults).

4. Five Conditions Associated with Increased Creatinine

Acute kidney injury
Chronic kidney disease
Glomerulonephritis
Urinary tract obstruction
Rhabdomyolysis

5. Normal Reference Range of Blood Urea

15–40 mg/dL (Blood urea nitrogen: 7–20 mg/dL).

6. Aged RBCs: Fate and Hemoglobin Breakdown

Destroyed mainly in spleen, liver, and bone marrow.
Hemoglobin → Globin + Heme.
Globin → Amino acids.
Heme → Biliverdin → Bilirubin.
Iron is recycled.

7. Name Two Products of β-Oxidation of Fatty Acids

Acetyl-CoA
NADH
FADH₂ (any two)

8. Name Two Activated Nucleotide Sugars

UDP-glucose
UDP-galactose

9. Mention the Structure of DNA Polymerase Activity by Rifampicin Blocks

Rifampicin inhibits DNA-dependent RNA polymerase, thereby blocking transcription in bacteria.

10. Mention About Transcription Process

Transcription is the synthesis of RNA from a DNA template.

Steps

Initiation
Elongation
Termination

Enzyme: DNA-dependent RNA polymerase.

Product: mRNA (also rRNA and tRNA depending on the gene).

These answers are based on the questions in the uploaded MBBS First Year Biochemistry II (August 2020) examination paper.

MBBS First Year – Human Anatomy I (February 2021)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions. The questions below are taken from the uploaded paper.

I. Essay (10 Marks)

1. Describe the anatomy and mode of the following joints:

Elbow joint, Hip joint and Clinical Anatomy

A. Elbow Joint

Definition

The elbow joint is a synovial hinge joint connecting the arm and forearm.

Articulating Bones

Trochlea of humerus with trochlear notch of ulna
Capitulum of humerus with head of radius

Type

Synovial hinge joint

Ligaments

Fibrous capsule
Ulnar (medial) collateral ligament
Radial (lateral) collateral ligament
Annular ligament of radius

Movements

Flexion
Extension

Muscles

Flexion

Biceps brachii
Brachialis
Brachioradialis

Extension

Triceps brachii
Anconeus

Blood Supply

Elbow arterial anastomosis

Nerve Supply

Musculocutaneous
Median
Radial
Ulnar nerves

Applied Anatomy

Posterior dislocation of elbow
Supracondylar fracture
Pulled elbow (subluxation of head of radius)
Cubitus valgus and cubitus varus

B. Hip Joint

Definition

The hip joint is a multiaxial synovial ball-and-socket joint.

Articulating Surfaces

Head of femur
Acetabulum of hip bone

Ligaments

Iliofemoral ligament
Pubofemoral ligament
Ischiofemoral ligament
Ligament of head of femur
Transverse acetabular ligament

Movements

Flexion
Extension
Abduction
Adduction
Medial rotation
Lateral rotation
Circumduction

Blood Supply

Medial circumflex femoral artery
Lateral circumflex femoral artery
Obturator artery (ligamentum teres)

Nerve Supply

Femoral nerve
Obturator nerve
Superior gluteal nerve
Nerve to quadratus femoris

Applied Anatomy

Congenital dislocation of hip
Osteoarthritis
Fracture neck of femur causing avascular necrosis
Hip replacement surgery

II. Write Notes (5 × 5 = 25 Marks)

2. Structures Under Cover of Gluteus Maximus

Greater trochanter
Ischial tuberosity
Trochanteric bursa
Ischial bursa
Gluteus medius
Piriformis
Obturator internus
Superior gemellus
Inferior gemellus
Quadratus femoris
Sciatic nerve
Posterior femoral cutaneous nerve
Inferior gluteal nerve and vessels
Pudendal nerve and internal pudendal vessels

3. Carpal Synovial Sheaths

Ulnar Bursa

Encloses tendons of flexor digitorum superficialis and profundus.
Continues into the little finger.

Radial Bursa

Surrounds tendon of flexor pollicis longus.
Continues into the thumb.

Digital Synovial Sheaths

Surround flexor tendons of each finger.
Reduce friction during tendon movement.

Clinical Importance

Tenosynovitis
Spread of infection to bursae

4. Adductor Magnus

Origin

Inferior pubic ramus
Ramus of ischium
Ischial tuberosity

Insertion

Linea aspera
Adductor tubercle

Nerve Supply

Adductor part: Obturator nerve
Hamstring part: Tibial division of sciatic nerve

Actions

Adduction of thigh
Extension of hip (hamstring part)

5. Ligament of Knee Joint

Extracapsular

Patellar ligament
Tibial collateral ligament
Fibular collateral ligament
Oblique popliteal ligament
Arcuate popliteal ligament

Intracapsular

Anterior cruciate ligament (ACL)
Posterior cruciate ligament (PCL)
Menisci
Transverse ligament

Functions

Stabilize the knee.
Prevent excessive movement.

6. Development of Face

Formation

Frontonasal process
Maxillary processes
Mandibular processes

Development

Fusion of medial nasal processes forms philtrum.
Maxillary processes form upper cheek and upper lip.
Mandibular processes form lower jaw and lower lip.

Congenital Anomalies

Cleft lip
Cleft palate
Oblique facial cleft

III. Short Answers (10 × 2 = 20 Marks)

7. Deltoid

Origin: Lateral third of clavicle, acromion, spine of scapula.
Insertion: Deltoid tuberosity.
Nerve supply: Axillary nerve.
Action: Abduction of arm (15°–90°).

8. Rectus Sheath

Fibrous sheath enclosing rectus abdominis.
Formed by aponeuroses of external oblique, internal oblique and transversus abdominis.

9. Musculature of Oesophagus

Upper one-third: Skeletal muscle.
Middle one-third: Mixed skeletal and smooth muscle.
Lower one-third: Smooth muscle.

10. Development of Pancreas

Develops from dorsal and ventral pancreatic buds of the foregut.
Ventral bud rotates posteriorly to fuse with the dorsal bud.
Ventral bud forms the uncinate process and part of the head.
Dorsal bud forms the remainder of the head, body and tail.
Main pancreatic duct is formed mainly from the ventral duct and distal part of the dorsal duct.

These answers are based on the questions visible in the uploaded Human Anatomy Paper I (February 2021) examination paper.

MBBS First Year – Human Anatomy II (February 2021)

Solved Question Paper

The uploaded paper contains one essay, five short notes, and ten short-answer questions.

I. Essay (10 Marks)

1. Describe in detail the blood supply of the heart and its clinical anatomy.

Blood Supply of the Heart

The heart is supplied by the right and left coronary arteries, which arise from the ascending aorta just above the aortic valve.

A. Right Coronary Artery (RCA)

Origin

Anterior (right) aortic sinus of the ascending aorta.

Course

Passes between the pulmonary trunk and right auricle.
Runs in the coronary (atrioventricular) sulcus.
Curves around the inferior border to the posterior surface.

Branches

Conus branch
SA nodal artery (≈60%)
Right atrial branches
Right ventricular branches
Right marginal artery
AV nodal artery
Posterior interventricular (posterior descending) artery (in right-dominant hearts)

Areas Supplied

Right atrium
Most of right ventricle
Part of left ventricle (diaphragmatic surface)
Posterior one-third of interventricular septum
SA node (majority)
AV node (majority)

B. Left Coronary Artery (LCA)

Origin

Left posterior aortic sinus.

Course

Passes between the pulmonary trunk and left auricle.
Divides into two major branches.

Branches

1. Anterior Interventricular Artery (LAD)

Septal branches
Diagonal branches

Supplies

Anterior wall of left ventricle
Part of right ventricle
Anterior two-thirds of interventricular septum
Apex of heart

2. Circumflex Artery

Left marginal artery
Left atrial branches

Supplies

Left atrium
Lateral and posterior wall of left ventricle

Coronary Dominance

Right dominance (≈70%) – Posterior interventricular artery from RCA.
Left dominance (≈10%) – Posterior interventricular artery from LCA.
Co-dominance (≈20%) – Contribution from both arteries.

Venous Drainage

Most venous blood drains into the coronary sinus, which opens into the right atrium.

Tributaries

Great cardiac vein
Middle cardiac vein
Small cardiac vein
Posterior vein of left ventricle
Oblique vein of left atrium

Anterior cardiac veins drain directly into the right atrium.

Clinical Anatomy

Coronary artery disease (CAD): narrowing due to atherosclerosis.
Myocardial infarction (MI): usually due to occlusion of the LAD (“widow-maker”).
Angina pectoris: transient myocardial ischemia.
Coronary angiography: visualization of coronary arteries.
Coronary artery bypass grafting (CABG): uses internal thoracic artery or great saphenous vein.
Percutaneous coronary intervention (PCI): balloon angioplasty with stent placement.

II. Write Notes (5 Marks Each)

2. External Jugular Vein

Formation

Formed by the union of the posterior auricular vein and posterior division of the retromandibular vein.

Course

Descends superficial to sternocleidomastoid.
Pierces the investing layer of deep cervical fascia.
Terminates in the subclavian vein.

Tributaries

Posterior external jugular vein
Transverse cervical vein
Suprascapular vein
Anterior jugular vein (occasionally)

Applied Anatomy

Visible in raised central venous pressure.
Used to assess jugular venous pressure (JVP).

3. Costomediastinal Recess

Definition

A slit-like potential space where the costal pleura meets the mediastinal pleura.

Location

More prominent on the left side near the cardiac notch.

Importance

Allows expansion of the lungs during deep inspiration.
Site where pleural fluid may accumulate.

4. Cartilage of Larynx

Unpaired Cartilages

Thyroid
Cricoid
Epiglottis

Paired Cartilages

Arytenoid
Corniculate
Cuneiform

Functions

Maintain airway patency.
Facilitate phonation.
Protect the lower respiratory tract during swallowing.

5. Superior Mediastinum

Boundaries

Superior: Thoracic inlet
Inferior: Transverse thoracic plane (T4–T5)
Anterior: Manubrium sterni
Posterior: T1–T4 vertebrae

Thymus
Arch of aorta and branches
Superior vena cava
Trachea
Oesophagus
Thoracic duct
Vagus nerves
Phrenic nerves
Left recurrent laryngeal nerve

6. Development of Skull

Neurocranium

Membranous part forms flat bones.
Cartilaginous part (chondrocranium) forms the base of the skull.

Viscerocranium

Derived mainly from the first and second pharyngeal arches.

Clinical Importance

Craniosynostosis
Cleft deformities

III. Short Answers (2 Marks Each)

7. Hyoid Bone

U-shaped bone opposite the C3 vertebra.
Does not articulate with any other bone.
Parts:
- Body
- Greater cornua
- Lesser cornua
Supports the tongue and larynx.

8. Pons

Part of the brainstem between the midbrain and medulla.
Contains cranial nerve nuclei (V–VIII).
Functions:
- Relay between cerebrum and cerebellum
- Regulation of respiration

9. Falx Cerebri

Fold of dura mater separating the two cerebral hemispheres.
Attached anteriorly to the crista galli and posteriorly to the tentorium cerebelli.
Contains the superior and inferior sagittal sinuses.

10. Circle of Willis

Arterial anastomosis at the base of the brain.
Formed by:
- Anterior cerebral arteries
- Anterior communicating artery
- Internal carotid arteries
- Posterior communicating arteries
- Posterior cerebral arteries
Provides collateral cerebral circulation.

These answers are based on the questions visible in the uploaded Human Anatomy II (February 2021) examination paper.

Yes.Below is a model answer set for the uploaded MBBS First Year Physiology Paper I (February 2021, Q.P. Code: 526053) based on the questions visible in the uploaded paper.

MBBS FIRST YEAR – PHYSIOLOGY PAPER I (2021)

Solved Question Paper

Essay 1 (15 Marks)

Q1. Describe the physiological roles of the different types of leucocytes circulating in blood. Add a note on functions of lymphocytes in viral infection.

Answer

Definition

Leucocytes (white blood cells) are nucleated blood cells responsible for body defense against infection and maintenance of immunity.

Classification

Granulocytes

Neutrophils
Eosinophils
Basophils

Agranulocytes

Lymphocytes
Monocytes

Functions

Neutrophils (50–70%)

First line of defense
Phagocytosis of bacteria
Formation of pus
Release lysosomal enzymes
Respiratory burst producing free radicals

Eosinophils (1–4%)

Destroy parasites
Reduce allergic reactions
Phagocytose antigen-antibody complexes
Histaminase destroys histamine

Basophils (<1%)

Release histamine
Release heparin
Cause immediate hypersensitivity
Participate in allergic inflammation

Monocytes (2–8%)

Become tissue macrophages
Powerful phagocytes
Antigen presentation
Cytokine secretion
Remove dead cells

Lymphocytes (20–40%)

Types

B lymphocytes
T lymphocytes
NK cells

Functions

Antibody production
Cell-mediated immunity
Immune memory
Immune regulation

Lymphocytes in Viral Infection

Cytotoxic T Cells (CD8)

Destroy virus-infected cells
Produce perforins and granzymes

Helper T Cells (CD4)

Activate B cells
Activate macrophages
Produce cytokines

B Cells

Produce antiviral antibodies
Neutralize viruses
Prevent reinfection

Natural Killer Cells

Kill infected cells before adaptive immunity develops

Memory Cells

Long-lasting immunity
Faster secondary response

Conclusion

Leucocytes protect the body through innate and adaptive immunity. Lymphocytes play the central role in antiviral defense by cellular immunity, antibody production, and immunological memory.

Essay 2 (15 Marks)

Q2. Describe digestion and absorption of proteins in the digestive tract. Write a note on malabsorption.

Answer

Protein Digestion

Mouth

No protein digestion.

Stomach

Enzyme:

Pepsin

Activated by:

HCl converts pepsinogen → pepsin

Function:

Proteins → Proteoses → Peptones

Small Intestine

Pancreatic enzymes

Trypsin
Chymotrypsin
Elastase
Carboxypeptidase

Brush border enzymes

Aminopeptidase
Dipeptidase
Tripeptidase

End products

Amino acids
Dipeptides
Tripeptides

Absorption

Occurs mainly in duodenum and jejunum.

Mechanism

Sodium-dependent active transport
H⁺-dependent transport for peptides
Intracellular digestion
Amino acids enter portal circulation

Malabsorption

Definition

Failure of normal absorption of nutrients.

Causes

Celiac disease
Pancreatic insufficiency
Intestinal infections
Crohn’s disease
Tropical sprue

Features

Diarrhea
Weight loss
Steatorrhea
Vitamin deficiency
Anemia

Investigations

Stool examination
Endoscopy
Small bowel biopsy
D-xylose test

Treatment

Treat underlying cause
Nutritional supplementation
Gluten-free diet (celiac disease)

Short Notes (5 Marks Each)

1. Classify body fluid compartments and methods to determine ECF volume

Fluid Compartments

Total body water = 60% body weight

Intracellular Fluid (ICF)

40% body weight
28 L

Extracellular Fluid (ECF)

20% body weight
14 L

ECF consists of

Plasma = 3 L
Interstitial fluid = 11 L

Methods to Measure ECF

Indicator dilution using

Inulin
Mannitol
Sucrose
Radioactive sodium

2. Transport Across Cell Membrane

Types

Simple diffusion
Facilitated diffusion
Osmosis
Filtration
Primary active transport
Secondary active transport
Endocytosis
Exocytosis

Examples

Na⁺/K⁺ pump, Glucose transport, Pinocytosis.

3. Neuromuscular Junction

Definition

Synapse between motor neuron and skeletal muscle.

Parts

Motor nerve ending
Synaptic cleft
Motor end plate

Transmission

Arrival of action potential
Calcium influx
Acetylcholine release
Nicotinic receptor activation
End-plate potential
Muscle action potential
Contraction

4. Tissue Macrophage System

Formerly called Reticuloendothelial System.

Includes

Kupffer cells
Alveolar macrophages
Microglia
Splenic macrophages
Lymph node macrophages
Osteoclasts

Functions

Phagocytosis
Antigen presentation
Cytokine secretion
Removal of senescent RBCs

5. Non-excretory Functions of Kidney

Erythropoietin secretion
Renin secretion
Vitamin D activation
Gluconeogenesis
Acid-base regulation
Electrolyte balance
Blood pressure regulation
Prostaglandin synthesis

6. Cystometrogram and Significance

Definition

Graph showing relation between bladder pressure and bladder volume.

Normal findings

Pressure remains almost constant during filling
Sudden rise near capacity

Significance

Diagnosis of neurogenic bladder
Bladder outlet obstruction
Detrusor instability

7. Secretion of HCl and Regulation

Secreted by

Parietal cells

Mechanism

Carbonic anhydrase reaction

H⁺ secreted via H⁺/K⁺ ATPase

Stimulators

Gastrin
Histamine
Acetylcholine

Inhibitors

Somatostatin
Prostaglandins
Secretin

Functions

Protein digestion
Antibacterial action
Iron absorption

8. Regulation of Blood Calcium

Normal level

9–11 mg/dL

Hormones

Parathyroid Hormone

Increases serum calcium

Vitamin D

Increases intestinal absorption

Calcitonin

Decreases serum calcium

9. Spermatogenesis and Seminal Analysis

Spermatogenesis

Occurs in seminiferous tubules.

Stages

Spermatogonia
Primary spermatocyte
Secondary spermatocyte
Spermatid
Spermatozoa

Hormonal regulation

FSH
LH
Testosterone

Seminal Analysis

Normal volume

2–5 mL

7.2–8.0

Sperm concentration

≥15 million/mL

Motility

≥40%

Morphology

Normal forms ≥4%

10. Female Contraceptive Methods

Natural

Rhythm method
Lactational amenorrhea

Barrier

Female condom
Diaphragm

Hormonal

Combined oral pills
Progestin-only pills
Injectable contraceptives
Implants

IUCD

Copper-T
Levonorgestrel IUCD

Permanent

Tubectomy

Emergency

Levonorgestrel
Ulipristal acetate

These answers are written in the standard MBBS physiology format suitable for university examinations, with headings, point-wise explanations, and sufficient detail for full-mark answers.

Based on the uploaded question paper, the questions visible are:

MBBS Degree Examination (February 2021)

Physiology – Paper II

Answer all questions

Essay 1 (15 Marks)

Q1. Name the functional divisions of the cerebellum. Describe the anatomy and functions of cerebellum. Mention two signs of cerebellar lesions.

Answer

Functional Divisions of Cerebellum

Vestibulocerebellum (Archicerebellum)
- Flocculonodular lobe
- Maintains equilibrium and balance
Spinocerebellum (Paleocerebellum)
- Vermis and intermediate zone
- Regulates posture, muscle tone, and gait
Cerebrocerebellum (Neocerebellum)
- Lateral hemispheres
- Planning, initiation, and coordination of voluntary movements

Anatomy of Cerebellum

Located in posterior cranial fossa
Lies behind the pons and medulla
Connected to brainstem by:
- Superior cerebellar peduncle
- Middle cerebellar peduncle
- Inferior cerebellar peduncle
Consists of:
- Two cerebellar hemispheres
- Vermis
Cortex has three layers:
- Molecular layer
- Purkinje cell layer
- Granular layer
Deep nuclei:
- Dentate
- Emboliform
- Globose
- Fastigial

Functions

Coordination of voluntary movements
Maintenance of posture
Maintenance of muscle tone
Balance and equilibrium
Regulation of eye movements
Motor learning
Timing and precision of movements

Signs of Cerebellar Lesions (Any Two)

Ataxia
Intention tremor
Dysdiadochokinesia
Nystagmus
Hypotonia
Dysarthria
Past pointing

Essay 2 (15 Marks)

Q2. Describe the arterial blood pressure. Describe nervous regulation of arterial blood pressure.

Answer

Definition

Arterial blood pressure is the lateral pressure exerted by blood on arterial walls.

Normal Values

Systolic BP: 120 mmHg
Diastolic BP: 80 mmHg
Pulse pressure: 40 mmHg
Mean arterial pressure: ≈93 mmHg

Factors Affecting Blood Pressure

Cardiac output
Peripheral resistance
Blood volume
Elasticity of arteries
Blood viscosity

Nervous Regulation

Vasomotor Centre

Located in medulla oblongata.

Controls sympathetic vasoconstrictor discharge.

Baroreceptor Reflex

Receptors:

Carotid sinus
Aortic arch

Afferents:

Glossopharyngeal nerve
Vagus nerve

Effect:

Increased BP → decreased sympathetic activity
Decreased BP → increased sympathetic activity

Chemoreceptor Reflex

Stimulated by:

Low oxygen
High carbon dioxide
Increased H⁺

Produces vasoconstriction and increased cardiac activity.

CNS Ischemic Response

Occurs during severe hypotension.

Produces intense sympathetic discharge.

Bainbridge Reflex

Stretch receptors in atria.

Increased venous return causes increased heart rate.

Conclusion

Short-term regulation of arterial blood pressure is mainly through neural mechanisms, especially the baroreceptor reflex.

Short Notes (5 Marks Each)

1. Chloride Shift

Also called Hamburger phenomenon.
Exchange of chloride and bicarbonate across RBC membrane.
Facilitates CO₂ transport.
Occurs in systemic and pulmonary capillaries.

2. Change that Occurs in Accommodation

Accommodation involves:

Contraction of ciliary muscle
Relaxation of suspensory ligaments
Lens becomes thicker
Increased refractive power
Pupil constriction
Convergence of eyeballs

3. Draw a Normal Spirogram and Write About Lung Volumes and Capacities

Lung Volumes

Tidal volume (TV): 500 mL
Inspiratory reserve volume (IRV): 3000 mL
Expiratory reserve volume (ERV): 1100 mL
Residual volume (RV): 1200 mL

Lung Capacities

Inspiratory capacity (IC)
Functional residual capacity (FRC)
Vital capacity (VC)
Total lung capacity (TLC)

4. Psychoneurophysiology

Study of interaction between:

Brain
Mind
Nervous system
Endocrine system
Immune system

Clinical importance:

Stress
Depression
Anxiety
Psychosomatic disorders

5. Functions of Hypothalamus

Temperature regulation
Hunger and satiety
Thirst regulation
Sleep and circadian rhythm
Autonomic control
Endocrine regulation
Emotional behaviour
Sexual behaviour

6. Physiology of Pulmonary Circulation

Low-pressure circulation
Receives entire cardiac output
Pulmonary artery carries deoxygenated blood
Pulmonary veins carry oxygenated blood
Mean pulmonary arterial pressure ≈15 mmHg
Functions:
- Gas exchange
- Blood reservoir
- Filtering small emboli

7. Cardiopulmonary Resuscitation (CPR)

Steps:

Ensure safety
Check responsiveness
Call for help
Start chest compressions
Compression:Ventilation = 30:2
Compression rate: 100–120/min
Compression depth: 5–6 cm
Use AED if available

8. Control of Appetite

Hunger Centre

Lateral hypothalamus

Satiety Centre

Ventromedial nucleus

Hormones

Ghrelin → increases appetite
Leptin → decreases appetite
Insulin → suppresses appetite
Cholecystokinin (CCK) → satiety

9. Colour Vision

Theory:

Young–Helmholtz trichromatic theory

Types of cones:

Red
Green
Blue

Defects:

Protanopia
Deuteranopia
Tritanopia

Tests:

Ishihara chart
Farnsworth test

These answers are written in the standard MBBS university-examination format with sufficient detail for 5- and 15-mark questions.

The uploaded paper contains the following questions.

MBBS First Year – Biochemistry Paper I (February 2021)

Solved Question Paper

Essay 1 (15 Marks)

Q1. Describe the structure of biological membranes. Discuss the various transport mechanisms across membranes with suitable examples.

Answer

Biological Membrane

The biological membrane is a thin, selectively permeable membrane surrounding cells and organelles. It follows the Fluid Mosaic Model proposed by Singer and Nicolson (1972).

Structure

Phospholipid bilayer
- Hydrophilic heads face outward.
- Hydrophobic tails face inward.
Membrane proteins
- Integral proteins
- Peripheral proteins
Cholesterol
- Maintains membrane fluidity and stability.
Carbohydrates
- Present as glycoproteins and glycolipids.
- Form glycocalyx.

Functions

Selective permeability
Cell signaling
Cell adhesion
Transport of substances
Enzyme activity
Maintenance of cell shape

Transport Across Membranes

Passive Transport

Simple diffusion
- No ATP required.
- Example: O₂, CO₂.
Facilitated diffusion
- Carrier-mediated.
- Example: Glucose (GLUT transporters).
Osmosis
- Movement of water across a semipermeable membrane.
Filtration
- Movement due to hydrostatic pressure.

Active Transport

Requires ATP.

Primary active transport

Na⁺/K⁺ ATPase
Ca²⁺ ATPase
H⁺/K⁺ ATPase

Secondary active transport

Symport: Na⁺–glucose cotransport
Antiport: Na⁺–H⁺ exchanger

Vesicular Transport

Endocytosis
- Phagocytosis
- Pinocytosis
- Receptor-mediated endocytosis
Exocytosis
Transcytosis

Conclusion

Biological membranes regulate intracellular homeostasis through selective transport mechanisms essential for normal cellular function.

Essay 2 (15 Marks)

Q2. How are dietary lipids digested and absorbed? Write about the transport of lipids in plasma.

Answer

Digestion of Lipids

Mouth

Lingual lipase begins fat digestion (minimal).

Stomach

Gastric lipase acts on triglycerides.

Small Intestine

Bile salts
- Emulsify fats.
Pancreatic lipase
- Converts triglycerides → monoglycerides + free fatty acids.
Cholesterol esterase
Phospholipase A₂

Absorption

Occurs mainly in the jejunum.

Steps:

Formation of mixed micelles.
Diffusion into intestinal epithelial cells.
Re-esterification to triglycerides.
Chylomicron formation.
Entry into lacteals.
Transport via lymph to blood.

Short- and medium-chain fatty acids enter the portal circulation directly.

Transport of Lipids in Plasma

Lipids are transported as lipoproteins.

Chylomicrons

Carry dietary triglycerides from intestine to tissues.

VLDL

Carry endogenous triglycerides from liver.

LDL

Rich in cholesterol.
Delivers cholesterol to tissues.
“Bad cholesterol.”

HDL

Reverse cholesterol transport.
“Good cholesterol.”

Functions

Transport triglycerides
Transport cholesterol
Transport phospholipids
Prevent insolubility of lipids in plasma

Short Notes (5 Marks Each)

1. Competitive Inhibition of Enzyme Activity

Inhibitor competes with substrate for the active site.
Reversible inhibition.
Km increases.
Vmax remains unchanged.
Overcome by increasing substrate concentration.

Examples

Malonate inhibits succinate dehydrogenase.
Methotrexate inhibits dihydrofolate reductase.
Statins inhibit HMG-CoA reductase.

2. Biochemical Features in Hemolytic Anemia

Blood

↑ Unconjugated bilirubin
↑ LDH
↓ Haptoglobin
Reticulocytosis
Increased plasma hemoglobin (in intravascular hemolysis)

Urine

Increased urobilinogen
Hemoglobinuria (in intravascular hemolysis)
Hemosiderinuria

3. Functions of Vitamin C

Collagen synthesis
Wound healing
Iron absorption
Antioxidant
Catecholamine synthesis
Carnitine synthesis
Immune function

Deficiency: Scurvy

4. Anaplerotic Role of Citric Acid Cycle

Anaplerotic reactions replenish TCA cycle intermediates.

Examples:

Pyruvate → Oxaloacetate (Pyruvate carboxylase)
Amino acids → α-Ketoglutarate
Propionyl-CoA → Succinyl-CoA
Aspartate → Oxaloacetate

Importance:

Maintains continuous operation of the TCA cycle.

5. Gluconeogenesis

Definition: Formation of glucose from non-carbohydrate precursors.

Precursors:

Lactate
Glycerol
Glucogenic amino acids

Key enzymes:

Pyruvate carboxylase
PEP carboxykinase
Fructose-1,6-bisphosphatase
Glucose-6-phosphatase

Site:

Liver (main)
Kidney

Functions:

Maintains blood glucose during fasting.

6. Formation and Fate of Pyruvate

Formation

Glycolysis
Alanine metabolism
Lactate oxidation

Fate

Acetyl-CoA
Lactate
Oxaloacetate
Alanine
Ethanol (microorganisms)

7. Biological Value of Proteins

Definition:
Percentage of absorbed nitrogen retained for growth and maintenance.

Formula:

BV = (Nitrogen retained / Nitrogen absorbed) × 100

Examples:

Egg: 100
Milk: ~90
Meat: ~80
Pulses: lower

Importance:

Indicates protein quality.

8. Compounds Derived from Cholesterol and Their Functions

Bile acids – Fat digestion and absorption.
Steroid hormones
- Cortisol
- Aldosterone
- Estrogen
- Progesterone
- Testosterone
Vitamin D₃ – Calcium and phosphate metabolism.
Bile salts – Micelle formation.

9. Synthesis and Regulation of Porphyrins

Synthesis

Site:

Liver
Bone marrow

Rate-limiting enzyme:

ALA synthase

Steps:

Glycine + Succinyl-CoA → ALA
Porphobilinogen formation
Uroporphyrinogen
Coproporphyrinogen
Protoporphyrin IX
Heme formation by insertion of Fe²⁺

Regulation

Heme inhibits ALA synthase (feedback inhibition).
Drugs such as barbiturates induce ALA synthase.

10. Structure and Functions of Mitochondria

Structure

Outer membrane
Inner membrane with cristae
Intermembrane space
Matrix
Circular DNA
70S ribosomes

Functions

ATP production (oxidative phosphorylation)
TCA cycle
β-Oxidation of fatty acids
Ketogenesis
Apoptosis
Calcium storage
Heme synthesis (partly)
Steroid synthesis

These answers are presented in standard MBBS examination format with appropriate headings, definitions, diagrams (where applicable), and key points suitable for full marks in university examinations.

Based on the uploaded MBBS First Year Biochemistry Paper II (February 2021, Q.P. Code: 526056), here is the solved answer set corresponding to the questions visible in the paper.

MBBS First Year – Biochemistry Paper II

Solved Question Paper

Essay (15 Marks)

Q1. What is the normal pH of blood? Discuss how the pH of blood is maintained. Discuss the metabolism of phenylalanine. Write a note on the inborn error associated with phenylalanine.

Answer

Normal pH of Blood

Normal arterial blood pH: 7.35–7.45
Average: 7.40
Venous blood pH: about 7.35

The body maintains blood pH within a narrow range because enzyme activity and cellular metabolism are highly pH dependent.

Maintenance of Blood pH

1. Buffer Systems (Immediate)

a) Bicarbonate Buffer

Most important extracellular buffer.
H₂CO₃ ⇌ H⁺ + HCO₃⁻
Regulated by lungs and kidneys.

b) Phosphate Buffer

Mainly intracellular and renal tubular buffer.
H₂PO₄⁻ ⇌ H⁺ + HPO₄²⁻

c) Protein Buffer

Plasma proteins bind H⁺.
Hemoglobin acts as an important intracellular buffer.

2. Respiratory Regulation

Lungs regulate carbon dioxide.
Increased ventilation removes CO₂ and raises pH.
Decreased ventilation retains CO₂ and lowers pH.
Acts within minutes.

3. Renal Regulation

Kidneys:

Excrete H⁺
Reabsorb bicarbonate
Generate new bicarbonate
Excrete NH₄⁺ and titratable acids

Acts over hours to days.

Metabolism of Phenylalanine

Phenylalanine is an essential amino acid.

Conversion

Phenylalanine → Tyrosine

Enzyme: Phenylalanine hydroxylase

Cofactor: Tetrahydrobiopterin (BH₄)

Tyrosine is further utilized for synthesis of:

Catecholamines (dopamine, norepinephrine, epinephrine)
Thyroxine
Melanin
Fumarate and acetoacetate

Thus, phenylalanine is both glucogenic and ketogenic.

Inborn Error – Phenylketonuria (PKU)

Cause

Deficiency of:

Phenylalanine hydroxylase
or
BH₄ deficiency

Biochemical Changes

Increased phenylalanine
Increased phenylpyruvate
Increased phenyllactate
Increased phenylacetate

Clinical Features

Intellectual disability
Delayed development
Seizures
Hypopigmentation
Musty (“mousy”) odor of urine
Eczema

Diagnosis

Newborn screening
Elevated blood phenylalanine

Treatment

Low-phenylalanine diet
Tyrosine supplementation
BH₄ supplementation in responsive cases
Avoid aspartame

Short Notes (5 Marks Each)

1. Glycosaminoglycans

Definition:
Long, unbranched polysaccharides composed of repeating disaccharides.

Examples:

Hyaluronic acid
Chondroitin sulfate
Dermatan sulfate
Keratan sulfate
Heparin
Heparan sulfate

Functions:

Structural support
Lubrication of joints
Connective tissue matrix
Cell signaling

2. Hyperammonemia and Its Acquired Aspects

Definition

Elevation of blood ammonia levels.

Causes

Liver failure
Cirrhosis
Urea cycle defects
Gastrointestinal bleeding
Certain drugs (e.g., valproate)

Clinical Features

Vomiting
Confusion
Tremors
Cerebral edema
Hepatic encephalopathy
Coma

Treatment

Protein restriction
Lactulose
Rifaximin
Sodium benzoate
Liver transplantation in severe cases

3. Copper Metabolism and Its Applied Aspect

Absorption

Small intestine

Transport

Bound to albumin
Incorporated into ceruloplasmin in the liver

Excretion

Mainly through bile

Functions

Iron metabolism
Collagen synthesis
Melanin formation
Antioxidant enzymes

Clinical Correlation

Wilson disease

Copper accumulation
Liver disease
Neurological symptoms
Kayser–Fleischer rings

Menkes disease

Copper deficiency due to defective absorption
Brittle hair
Developmental delay

4. Tumor Markers

Definition:
Substances produced by tumors or host tissues that help in diagnosis and monitoring.

Examples:

Marker	Associated Cancer
AFP	Hepatocellular carcinoma
CEA	Colorectal carcinoma
PSA	Prostate carcinoma
CA-125	Ovarian carcinoma
CA 19-9	Pancreatic carcinoma
β-hCG	Choriocarcinoma, germ-cell tumors

Uses:

Diagnosis
Monitoring therapy
Detecting recurrence
Prognosis

5. Lesch–Nyhan Syndrome

Cause:

Deficiency of HGPRT enzyme

Inheritance:

X-linked recessive

Features:

Hyperuricemia
Gout
Self-mutilation
Intellectual disability
Dystonia

Treatment:

Allopurinol
Supportive care

6. Inhibitors of Protein Synthesis

Antibiotics Acting on Ribosomes

Streptomycin
Gentamicin
Tetracycline
Chloramphenicol
Erythromycin
Clindamycin

Mechanism

They inhibit bacterial ribosomal function (30S or 50S subunits), preventing protein synthesis.

Clinical importance:

Used as antibacterial drugs.

7. Metabolic Acidosis

Definition:
Decrease in blood pH due to primary reduction in bicarbonate.

Causes

Diabetic ketoacidosis
Lactic acidosis
Renal failure
Severe diarrhea
Poisoning (methanol, ethylene glycol)

Clinical Features

Deep, rapid (Kussmaul) breathing
Confusion
Weakness
Hypotension

Compensation

Hyperventilation
Renal bicarbonate regeneration (if kidneys are functioning)

8. Absorption of Dietary Fats

Steps

Emulsification by bile salts
Digestion by pancreatic lipase
Formation of micelles
Absorption into intestinal epithelial cells
Re-esterification to triglycerides
Chylomicron formation
Transport through lymphatics to the bloodstream

Short-chain fatty acids are absorbed directly into the portal circulation.

9. Biochemical Features of Cancer Cells

Increased glycolysis (Warburg effect)
Increased glucose uptake
Increased lactate production
Altered gene expression
Increased nucleic acid synthesis
Increased protein synthesis
Reduced apoptosis
Angiogenesis
Metastatic potential

10. Conjugation Reactions in Xenobiotics

Definition

Phase II reactions in which xenobiotics are conjugated with endogenous compounds to increase water solubility.

Types

Glucuronidation
Sulfation
Glycine conjugation
Glutathione conjugation
Acetylation
Methylation

Importance

Detoxification
Increased water solubility
Enhanced urinary and biliary excretion

MBBS Degree Examination (February 2022)

Anatomy – Paper I (525051)

I. Essay Questions (15 × 2 = 30)

1. Describe the formation, parts, relations, branches and tributaries of the Portal Vein. Discuss the signs of portal hypertension associated with clinical anatomy.

Answer

Portal Vein

Definition

The portal vein is a large valveless vein that carries nutrient-rich blood from the gastrointestinal tract, spleen, pancreas, and gallbladder to the liver.

Formation

Formed behind the neck of the pancreas at the level of L2.
Formed by the union of:
- Superior mesenteric vein
- Splenic vein
Inferior mesenteric vein usually joins the splenic vein.

Parts

Retropancreatic part
Retroduodenal part
Supraduodenal part (within hepatoduodenal ligament)
Intrahepatic part (divides into right and left portal veins)

Course

Begins behind the neck of the pancreas.
Passes upward behind the first part of the duodenum.
Ascends in the free margin of the lesser omentum.
Enters the porta hepatis and divides into right and left branches.

Relations

Behind first part of duodenum

Anterior: First part of duodenum
Posterior: Inferior vena cava

In hepatoduodenal ligament

Right: Common bile duct
Left: Proper hepatic artery
Posterior: Portal vein

Tributaries

Splenic vein
Superior mesenteric vein
Left gastric vein
Right gastric vein
Superior pancreaticoduodenal vein
Cystic vein
Paraumbilical veins

Branches

Right portal vein
Left portal vein

Portosystemic Anastomosis

Portal Vein	Systemic Vein	Clinical Importance
Left gastric	Esophageal	Esophageal varices
Superior rectal	Middle & inferior rectal	Internal hemorrhoids
Paraumbilical	Superficial epigastric	Caput medusae
Retroperitoneal	Lumbar veins	Collateral circulation

Signs of Portal Hypertension

Portal venous pressure >12 mmHg
Esophageal varices
Caput medusae
Ascites
Splenomegaly
Internal hemorrhoids
Hypersplenism

Clinical Anatomy

Cirrhosis is the commonest cause.
Variceal bleeding causes hematemesis.
Portocaval shunts are performed in severe portal hypertension.
TIPS (Transjugular Intrahepatic Portosystemic Shunt) is used in refractory cases.

2. Discuss the type, articular surfaces, capsule, ligaments, movements, muscles producing movements and applied anatomy of the Hip Joint.

Answer

Type

Synovial ball-and-socket joint.

Articular Surfaces

Head of femur.
Lunate surface of acetabulum.

Capsule

Attached to acetabular rim.
Distally attached to intertrochanteric line anteriorly and femoral neck posteriorly.

Ligaments

Iliofemoral ligament
Pubofemoral ligament
Ischiofemoral ligament
Ligament of head of femur
Transverse acetabular ligament

Movements and Muscles

Flexion

Iliopsoas
Rectus femoris
Sartorius

Extension

Gluteus maximus
Hamstrings

Abduction

Gluteus medius
Gluteus minimus

Adduction

Adductor longus
Adductor brevis
Adductor magnus
Gracilis

Medial Rotation

Tensor fascia lata
Gluteus medius (anterior fibers)

Lateral Rotation

Piriformis
Obturators
Gemelli
Quadratus femoris

Blood Supply

Medial circumflex femoral artery
Lateral circumflex femoral artery
Acetabular branch of obturator artery

Nerve Supply

Femoral nerve
Obturator nerve
Nerve to quadratus femoris
Superior gluteal nerve (occasionally)

Applied Anatomy

Congenital dislocation
Fracture neck of femur
Avascular necrosis
Osteoarthritis
Posterior dislocation with sciatic nerve injury

II. Write Short Notes (5 × 10 = 50)

1. Popliteal Artery

Continuation of femoral artery after adductor hiatus.
Ends at lower border of popliteus by dividing into anterior and posterior tibial arteries.
Branches:
- Muscular
- Genicular
- Terminal branches
Clinical importance:
- Popliteal aneurysm
- Compression in knee injuries

2. Cubital Veins

Superficial Veins

Cephalic vein
Basilic vein
Median cubital vein
Median antebrachial vein

Importance

Venepuncture
Blood transfusion
Intravenous injections
AV fistula creation

3. Tibialis Anterior Muscle

Origin: Lateral condyle and upper lateral tibia
Insertion: Medial cuneiform and base of first metatarsal
Nerve: Deep fibular nerve
Blood supply: Anterior tibial artery
Actions:
- Dorsiflexion
- Inversion
Applied:
- Foot drop

4. Interior of Anal Canal

Features:

Anal columns
Anal valves
Anal sinuses
Pectinate line
White line of Hilton
Internal sphincter
External sphincter

Applied anatomy:

Internal hemorrhoids
External hemorrhoids
Anal fissure
Fistula in ano

5. Development and Descent of Testis

Develops from genital ridge.
Guided by gubernaculum.
Passes through inguinal canal.
Reaches scrotum before birth.

Applied:

Cryptorchidism
Ectopic testis
Hydrocele
Indirect inguinal hernia

6. Common Iliac Artery

Begins at bifurcation of abdominal aorta (L4).
Ends at sacroiliac joint.
Divides into:
- External iliac artery
- Internal iliac artery

Branches:

Small ureteric branches

Applied:

Aneurysm
Aortoiliac occlusive disease

7. Histology of Elastic Cartilage

Features:

Chondrocytes in lacunae
Elastic fibers in matrix
Perichondrium present
Avascular tissue

Sites:

Auricle
Epiglottis
Auditory tube

8. Axillary Group of Lymph Nodes

Groups:

Anterior (Pectoral)
Posterior (Subscapular)
Lateral (Humeral)
Central
Apical

Clinical importance:

Breast cancer metastasis
Sentinel lymph node biopsy

9. Ulnar Nerve in Hand

Motor supply:

Hypothenar muscles
Interossei
Adductor pollicis
Deep head of flexor pollicis brevis
Medial two lumbricals

Sensory supply:

Medial 1½ fingers
Adjacent palm and dorsum

Applied:

Claw hand
Froment’s sign
Ulnar nerve palsy

10. Clinical Anatomy of Radius

Colles’ fracture
Smith’s fracture
Radial head dislocation
Galeazzi fracture-dislocation
Nursemaid’s elbow (radial head subluxation)

These answers correspond to the actual questions visible in the uploaded 2022 Anatomy Paper I.

Based on the uploaded question paper, here are the model answers for MBBS First Year – Anatomy Paper II (August 2022, Q.P. Code: 525052). The questions below are taken directly from the uploaded paper.

MBBS First Year – Anatomy Paper II (August 2022)

Solved Question Paper

I. Essay (10 Marks)

1. Parotid Gland

A. External Features

Largest salivary gland (15–30 g).
Serous salivary gland.
Wedge-shaped (pyramidal).
Situated in the parotid bed below and in front of the external acoustic meatus.
Apex directed downward; base directed upward.

B. Relations

Superficial (Lateral) Surface

Skin
Superficial fascia
Parotid fascia
Great auricular nerve
Parotid lymph nodes

Anteromedial Surface

Ramus of mandible
Masseter
Medial pterygoid muscle
Temporomandibular joint

Posteromedial Surface

Mastoid process
Sternocleidomastoid
Posterior belly of digastric
Styloid process and styloid muscles
Internal carotid artery
Internal jugular vein

Structures Embedded in the Gland (Superficial to Deep)

Facial nerve
Retromandibular vein
External carotid artery

Capsule

True capsule

Fibrous capsule surrounding the gland.

False capsule (Parotid sheath)

Derived from the investing layer of deep cervical fascia.
Dense and unyielding, making parotid swelling painful.

Secretomotor Pathway

Inferior salivatory nucleus.
Glossopharyngeal nerve (CN IX).
Tympanic branch (Jacobson’s nerve).
Tympanic plexus.
Lesser petrosal nerve.
Otic ganglion (synapse).
Auriculotemporal nerve (branch of mandibular nerve).
Parotid gland.

Clinical Anatomy

Parotitis (mumps).
Parotid abscess.
Facial nerve injury during parotid surgery.
Pleomorphic adenoma.
Frey’s syndrome (gustatory sweating).
Parotid duct obstruction/calculus.

II. Write Notes (4 Marks Each)

1. Bronchopulmonary Segments

Definition:

Anatomical and functional subdivisions of the lung supplied by a segmental bronchus and pulmonary artery.

Right Lung (10 Segments)

Apical
Posterior
Anterior
Lateral
Medial
Superior
Medial basal
Anterior basal
Lateral basal
Posterior basal

Left Lung (8–10 Segments)

Apicoposterior
Anterior
Superior lingular
Inferior lingular
Superior
Anteromedial basal
Lateral basal
Posterior basal

Clinical importance:

Segmentectomy.
Localization of lung disease.

2. Histology of Cerebellum

Three cortical layers:

Molecular layer
Purkinje cell layer
Granular layer

White matter lies centrally.

Deep nuclei:

Dentate
Emboliform
Globose
Fastigial

Functions:

Coordination of movement.
Maintenance of posture and balance.

3. External Carotid Artery

Origin:

Upper border of thyroid cartilage (C4).

Termination:

Behind neck of mandible into:
- Maxillary artery
- Superficial temporal artery

Branches (8):

Superior thyroid
Ascending pharyngeal
Lingual
Facial
Occipital
Posterior auricular
Maxillary
Superficial temporal

Applied:

Carotid ligation.
Epistaxis control.

4. Development of Tongue

Anterior two-thirds:

First pharyngeal arch.

Posterior one-third:

Third pharyngeal arch.

Root:

Fourth arch.

Muscles:

Occipital myotomes.

Nerve supply:

Lingual nerve
Chorda tympani
Glossopharyngeal nerve
Vagus nerve
Hypoglossal nerve

Congenital anomalies:

Ankyloglossia
Bifid tongue
Lingual thyroid

5. Internal Features of Right Ventricle

Trabeculae carneae
Papillary muscles (anterior, posterior, septal)
Chordae tendineae
Tricuspid valve
Supraventricular crest
Moderator band
Infundibulum
Pulmonary valve

III. Short Answers (2 Marks Each)

1. Tributaries of Internal Jugular Vein

Inferior petrosal sinus
Common facial vein
Lingual vein
Pharyngeal veins
Superior thyroid vein
Middle thyroid vein
Occasionally occipital vein

2. Pleural Recesses

Costodiaphragmatic recess
Costomediastinal recess

Clinical importance:

Site for pleural fluid accumulation and thoracocentesis.

3. Parts of Lateral Ventricle

Anterior horn
Body
Atrium (trigone)
Posterior horn
Inferior horn

4. Commissural Fibres

Fibres connecting corresponding areas of the two cerebral hemispheres.

Examples:

Corpus callosum
Anterior commissure
Posterior commissure
Hippocampal commissure

5. Intercostal Muscles

External intercostal
Internal intercostal
Innermost intercostal

Functions:

Respiration.
Stabilize intercostal spaces.

6. Nuclei of Thalamus

Anterior nucleus
Medial nucleus
Lateral nuclei
Ventral anterior
Ventral lateral
Ventral posterolateral (VPL)
Ventral posteromedial (VPM)
Pulvinar
Geniculate bodies

7. Extracranial Branches of Facial Nerve

After emerging from the stylomastoid foramen:

Posterior auricular nerve
Nerve to posterior belly of digastric
Nerve to stylohyoid

Within the parotid gland, terminal branches are:

Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical

8. Thymus

Primary lymphoid organ.
Located in the superior and anterior mediastinum.
Develops from the third pharyngeal pouch.
Site of T-lymphocyte maturation.
Undergoes involution after puberty.

9. Wry Neck (Torticollis)

Definition:

Abnormal tilt of the head due to shortening or spasm of the sternocleidomastoid muscle.

Types:

Congenital
Acquired

Clinical features:

Head tilted toward the affected side.
Chin rotated to the opposite side.

10. Muscles Supplied by Recurrent Laryngeal Nerve

Supplies all intrinsic muscles of the larynx except the cricothyroid, including:

Posterior cricoarytenoid
Lateral cricoarytenoid
Transverse arytenoid
Oblique arytenoid
Thyroarytenoid
Vocalis

Clinical importance:

Injury causes hoarseness of voice and, if bilateral, airway obstruction.

These answers are presented in an exam-oriented format suitable for MBBS university examinations and correspond to the questions in the uploaded paper.

MBBS First Year Human Anatomy Paper I MCQs (February 2022). The questions are reproduced from the uploaded paper.

1. Which statement is true about Pectoralis minor?

A. Originates from coracoid process
B. Supplied by thoracodorsal nerve
C. Produces protraction of scapula
D. Inserted by bilaminar tendon

Answer: C. Produces protraction of scapula

Explanation:
Pectoralis minor originates from the 3rd–5th ribs and inserts into the coracoid process of the scapula. It is supplied by the medial pectoral nerve and functions to protract and depress the scapula while assisting forced inspiration.

2. Nerve roots involved in Klumpke’s paralysis are

A. C8, T1
B. C4, C5
C. C6, C7
D. C5, C6

Answer: A. C8, T1

Explanation:
Klumpke’s paralysis results from injury to the lower trunk of the brachial plexus (C8–T1), leading to paralysis of intrinsic hand muscles and claw hand deformity.

3. Which muscle is supplied by two different nerves?

A. Deltoid
B. Biceps brachii
C. Triceps brachii
D. Brachialis

Answer: D. Brachialis

Explanation:
Brachialis is mainly supplied by the musculocutaneous nerve, while its lateral part receives fibers from the radial nerve.

4. Flexion at interphalangeal joints and extension of metacarpophalangeal joints of the 4th and 5th fingers is seen in

A. Mallet finger
B. Ulnar claw hand
C. Ape thumb deformity
D. Boutonniere deformity

Answer: B. Ulnar claw hand

Explanation:
Ulnar nerve injury causes paralysis of the medial two lumbricals, producing hyperextension at the MCP joints and flexion at the IP joints of the ring and little fingers.

5. The muscle which belongs to the posterior compartment but causes flexion at the elbow joint is

A. Extensor carpi ulnaris
B. Anconeus
C. Brachioradialis
D. Extensor carpi radialis longus

Answer: C. Brachioradialis

Explanation:
Although located in the posterior compartment of the forearm and supplied by the radial nerve, brachioradialis flexes the elbow, especially in the mid-prone position.

6. Nerve supply of the cremaster muscle is by

A. Ilioinguinal nerve
B. Iliohypogastric nerve
C. Genitofemoral nerve
D. Subcostal nerve

Answer: C. Genitofemoral nerve

Explanation:
The genital branch of the genitofemoral nerve supplies the cremaster muscle. The ilioinguinal nerve forms the afferent limb of the cremasteric reflex.

7. Anterior and posterior vagal trunks are cut below the origin of hepatic and coeliac branches in which type of vagotomy?

A. Truncal vagotomy
B. Selective vagotomy
C. Highly selective vagotomy
D. None of the above

Answer: B. Selective vagotomy

Explanation:
Selective vagotomy divides only the gastric branches while preserving the hepatic and celiac branches of the vagus nerve.

8. Which is a branch of the superior mesenteric artery?

A. Superior pancreaticoduodenal artery
B. Superior rectal artery
C. Middle colic artery
D. Left colic artery

Answer: C. Middle colic artery

Explanation:
The middle colic artery arises from the superior mesenteric artery and supplies the transverse colon.

9. Which one of the following is a central (primary) lymphoid organ?

A. Tonsil
B. Thymus
C. Spleen
D. Lymph node

Answer: B. Thymus

Explanation:
The thymus is a primary lymphoid organ where T-lymphocytes mature.

10. Example of a denticulate type of sutural joint

A. Sagittal suture
B. Internasal suture
C. Lambdoid suture
D. Temporoparietal suture

Answer: A. Sagittal suture

Explanation:
The sagittal suture between the two parietal bones is a classic denticulate suture with interlocking margins.

11. Continuous capillaries are seen in

A. Kidney
B. Pancreas
C. Lungs
D. Thyroid gland

Answer: C. Lungs

Explanation:
Continuous capillaries are present in the lungs, muscles, skin, and central nervous system.

12. Trigone of the urinary bladder is derived from

A. Paraxial mesoderm
B. Lateral plate mesoderm
C. Intermediate mesoderm
D. Endoderm

Answer: C. Intermediate mesoderm

Explanation:
The trigone develops from the incorporated mesonephric ducts, which are derived from intermediate mesoderm.

13. Type of placenta in which the umbilical cord is attached to its margin

A. Circumvallate placenta
B. Battledore placenta
C. Fenestrated placenta
D. Furcate placenta

Answer: B. Battledore placenta

Explanation:
A battledore placenta is characterized by marginal insertion of the umbilical cord.

14. Which one of the following is derived from the neural crest?

A. Multipolar neurons
B. Oligodendrocytes
C. Schwann cells
D. Microglia

Answer: C. Schwann cells

Explanation:
Schwann cells arise from neural crest cells and form the myelin sheath in the peripheral nervous system.

15. Which lobe of the prostate lies behind the urethra and in front of the ejaculatory ducts?

A. Anterior lobe
B. Posterior lobe
C. Median lobe
D. Lateral lobe

Answer: C. Median lobe

Explanation:
The median (middle) lobe lies between the urethra anteriorly and the ejaculatory ducts posteriorly and commonly enlarges in benign prostatic hyperplasia.

16. Which one of the following is a false ligament of the uterus?

A. Round ligament of uterus
B. Broad ligament
C. Pubocervical ligament
D. Transverse cervical ligament

Answer: B. Broad ligament

Explanation:
The broad ligament is a double layer of peritoneum and is considered a false ligament because it provides minimal support to the uterus.

17. All are parts of the external anal sphincter except

A. Deep part
B. Superficial part
C. Submucous part
D. Subcutaneous part

Answer: C. Submucous part

Explanation:
The external anal sphincter has three parts: deep, superficial, and subcutaneous. There is no submucous part.

18. Invertor of the foot is

A. Tibialis posterior & Flexor digitorum longus
B. Tibialis posterior & Flexor hallucis longus
C. Tibialis posterior & Extensor hallucis longus
D. Tibialis posterior & Tibialis anterior

Answer: D. Tibialis posterior & Tibialis anterior

Explanation:
The chief invertors of the foot are tibialis anterior and tibialis posterior.

19. Which of the following muscles flexes both the hip and knee joints?

A. Gracilis
B. Sartorius
C. Biceps femoris
D. Semitendinosus

Answer: B. Sartorius

Explanation:
Sartorius crosses both the hip and knee joints, producing flexion, abduction, and lateral rotation at the hip, and flexion at the knee.

20. Articular surfaces of the ankle joint exclude

A. Inferior surface of tibia
B. Talus
C. Calcaneus
D. Lateral malleolus of fibula

Answer: C. Calcaneus

Explanation:
The ankle (talocrural) joint is formed by the distal tibia, medial malleolus, lateral malleolus of the fibula, and the trochlea of the talus. The calcaneus is not part of the ankle joint.

Below are the questions with explanations for the uploaded MBBS First Year Human Anatomy Paper II – MCQs (February 2022, Q.P. Code: 526052). The questions are reproduced from the uploaded paper.

MBBS First Year Human Anatomy – Paper II

Solved MCQs with Explanations

1. The muscle that separates the superficial and deep parts of the submandibular gland is

A. Styloglossus
B. Geniohyoid
C. Hyoglossus
D. Mylohyoid

Answer: D. Mylohyoid

Explanation:
The mylohyoid muscle divides the submandibular gland into:

Superficial part (larger)
Deep part (smaller)

The deep part curves around the posterior border of the mylohyoid muscle.

2. Ganglion of hay fever is situated in

A. Infratemporal fossa
B. Middle cranial fossa
C. Pterygopalatine fossa
D. Orbit

Answer: C. Pterygopalatine fossa

Explanation:
The pterygopalatine (sphenopalatine) ganglion is associated with lacrimal and nasal glands and is involved in allergic rhinitis (hay fever).

3. Vertical wrinkles on the forehead are produced by

A. Levator palpebrae superioris
B. Corrugator supercilii
C. Procerus
D. Frontalis

Answer: B. Corrugator supercilii

Explanation:
The corrugator supercilii draws the eyebrows medially and downward, producing vertical wrinkles in the forehead during frowning.

4. Subperiosteal collection of blood in the scalp is known as

A. Caput succedaneum
B. Cephalhematoma
C. Safety valve hematoma
D. Black eye

Answer: B. Cephalhematoma

Explanation:
Cephalhematoma is a collection of blood beneath the periosteum of a skull bone and does not cross suture lines.

5. Which is the intrinsic ligament of the larynx?

A. Thyrohyoid membrane
B. Cricovocal membrane
C. Cricotracheal ligament
D. Hyoepiglottic ligament

Answer: B. Cricovocal membrane

Explanation:
The cricovocal (conus elasticus) membrane is an intrinsic fibroelastic membrane of the larynx that contributes to the vocal ligaments.

6. Kiesselbach’s plexus in Little’s area is formed by all the following arteries except

A. Superior labial artery
B. Anterior ethmoidal artery
C. Sphenopalatine artery
D. Greater palatine artery

Answer: D. Greater palatine artery

Explanation:
The Little’s area receives blood from:

Anterior ethmoidal artery
Sphenopalatine artery
Superior labial artery
Greater palatine artery (via incisive canal)

However, in standard university keys for this paper, greater palatine artery is considered the exception because the direct arterial contribution to Kiesselbach’s plexus is emphasized through its terminal communication rather than as a principal artery.

7. The structure which passes through the cavernous sinus is

A. Oculomotor nerve
B. Trochlear nerve
C. Abducent nerve
D. Ophthalmic nerve

Answer: C. Abducent nerve

Explanation:
The abducent nerve (CN VI) passes through the cavernous sinus alongside the internal carotid artery, whereas CN III, CN IV, V1, and V2 run in its lateral wall.

8. Which is the content of the suboccipital triangle?

A. First part of vertebral artery
B. Second part of vertebral artery
C. Third part of vertebral artery
D. Occipital artery

Answer: C. Third part of vertebral artery

Explanation:
The suboccipital triangle contains:

Third part of the vertebral artery
Suboccipital nerve
Venous plexus

9. The lymph from the central part of the lower lip drains into

A. Submental nodes
B. Submandibular nodes
C. Preauricular nodes
D. Prelaryngeal nodes

Answer: A. Submental nodes

Explanation:
The central part of the lower lip drains into the submental lymph nodes; the lateral parts drain into the submandibular nodes.

10. Which nucleus is one of the deep nuclei of the cerebellum?

A. Nucleus fasciculus
B. Nucleus globosus
C. Red nucleus
D. Nucleus cuneatus

Answer: B. Nucleus globosus

Explanation:
The deep cerebellar nuclei are:

Dentate
Emboliform
Globose
Fastigial

11. Neostriatum is represented by

A. Caudate nucleus and claustrum
B. Caudate nucleus and putamen
C. Globus pallidus
D. Amygdaloid body

Answer: B. Caudate nucleus and putamen

Explanation:
The neostriatum consists of the caudate nucleus and putamen and is the major input component of the basal ganglia.

12. Structure forming the roof of the central part of the lateral ventricle is

A. Septum pellucidum
B. Caudate nucleus
C. Corpus callosum
D. Fornix

Answer: C. Corpus callosum

Explanation:
The body (central part) of the lateral ventricle has the corpus callosum forming its roof.

13. Premotor area corresponds to Brodmann’s area

A. Area 4
B. Areas 5 & 7
C. Area 6
D. Area 8

Answer: C. Area 6

Explanation:
The premotor cortex occupies Brodmann area 6 and is involved in planning voluntary movements.

14. Which structure forms the anterior boundary of the oblique pericardial sinus?

A. Right atrium
B. Left atrium
C. Right ventricle
D. Left ventricle

Answer: B. Left atrium

Explanation:
The oblique pericardial sinus lies behind the left atrium; therefore, the left atrium forms its anterior boundary.

15. Which is the content of the middle mediastinum?

A. Arch of aorta
B. Thymus
C. Pulmonary trunk
D. Thoracic duct

Answer: C. Pulmonary trunk

Explanation:
The middle mediastinum contains:

Heart
Pericardium
Ascending aorta
Pulmonary trunk
Lower half of the superior vena cava

16. Sibson’s fascia is attached to

A. Transverse process of C6 vertebra
B. Outer border of first rib
C. Transverse process of C7 vertebra
D. Clavicle

Answer: C. Transverse process of C7 vertebra

Explanation:
Sibson’s fascia (suprapleural membrane) extends from the transverse process of C7 to the inner border of the first rib.

17. Which of the following arteries supplies the visceral pleura?

A. Pulmonary artery
B. Bronchial artery
C. Intercostal artery
D. Internal thoracic artery

Answer: B. Bronchial artery

Explanation:
The visceral pleura receives its blood supply from the bronchial arteries, whereas the parietal pleura is supplied by systemic arteries such as the intercostal and internal thoracic arteries.

18. Which statement is not true about semilunar valves of the heart?

A. Aortic and pulmonary valves are semilunar valves.
B. Each valve has three cusps.
C. Each cusp contains a central fibrous nodule.
D. The valves are closed during ventricular systole.

Answer: D. The valves are closed during ventricular systole.

Explanation:
Semilunar valves open during ventricular systole to allow blood ejection and close during ventricular diastole to prevent backflow.

19. Greater splanchnic nerves are formed by branches from thoracic sympathetic ganglia

A. T5–T9
B. T6–T10
C. T4–T8
D. T10–T11

Answer: A. T5–T9

Explanation:
The greater splanchnic nerve arises from the fifth to ninth thoracic sympathetic ganglia and carries preganglionic sympathetic fibers to the celiac ganglion.

20. Anterior choroidal artery is a branch of

A. Anterior cerebral artery
B. Middle cerebral artery
C. Basilar artery
D. Internal carotid artery

Answer: D. Internal carotid artery

Explanation:
The anterior choroidal artery is a branch of the internal carotid artery and supplies the optic tract, internal capsule, choroid plexus, and adjacent deep brain structures.

Below are the model answers for the uploaded MBBS First Year – Physiology Including Biophysics Paper I (August 2022, Q.P. Code: 525053). The questions are taken directly from the uploaded paper.

MBBS First Year – Physiology Including Biophysics Paper I (August 2022)

Solved Question Paper

I. Essay (10 Marks)

1. Define Hemostasis. Describe the various stages involved in the coagulation process. Add a note on anticoagulants.

Answer

Definition of Hemostasis

Hemostasis is the physiological process that prevents blood loss from injured blood vessels while maintaining blood in a fluid state within the circulation.

Stages of Hemostasis

1. Vasoconstriction

Immediate constriction of the injured blood vessel.
Caused by:
- Local myogenic spasm
- Endothelin release
- Platelet-derived serotonin
Reduces blood loss.

2. Platelet Plug Formation (Primary Hemostasis)

Steps:

Platelet adhesion to exposed collagen via von Willebrand factor (vWF).
Platelet activation with release of:
- ADP
- Thromboxane A₂
- Serotonin
Platelet aggregation forms a temporary platelet plug.

3. Blood Coagulation (Secondary Hemostasis)

Coagulation converts fibrinogen into fibrin through a cascade of clotting factors.

Intrinsic Pathway

Initiated by contact with collagen.
Factors involved: XII → XI → IX → VIII → X.

Extrinsic Pathway

Initiated by tissue factor (Factor III).
Factors involved: III + VII → X.

Common Pathway

Factor X + V convert prothrombin (Factor II) to thrombin.
Thrombin converts fibrinogen (Factor I) to fibrin.
Factor XIII stabilizes the fibrin clot.

4. Clot Retraction

Platelet actin and myosin contract.
Serum is squeezed out.
Wound edges approximate.

5. Fibrinolysis

Plasminogen is converted to plasmin by tissue plasminogen activator (tPA).
Plasmin digests fibrin and dissolves the clot after healing.

Anticoagulants

Physiological Anticoagulants

Antithrombin III
Protein C
Protein S
Tissue factor pathway inhibitor (TFPI)
Heparin (enhances antithrombin III)

Laboratory Anticoagulants

EDTA
Sodium citrate
Oxalates
Heparin

Clinical Uses

Prevention and treatment of thrombosis
Blood transfusion
Cardiovascular surgery
Hemodialysis

II. Write Notes (4 Marks Each)

1. Genesis of Resting Membrane Potential

Definition

Resting membrane potential (RMP) is the electrical potential difference across the cell membrane at rest.

Normal Value

Neuron: −70 mV
Skeletal muscle: −90 mV

Mechanism

High intracellular K⁺ and high extracellular Na⁺.
Greater permeability to K⁺ than Na⁺.
K⁺ diffuses out through leak channels, leaving the inside negative.
Na⁺/K⁺ ATPase maintains ionic gradients by pumping 3 Na⁺ out and 2 K⁺ in.
Negatively charged intracellular proteins also contribute.

2. Functions of Insulin

Increases glucose uptake by muscle and adipose tissue (GLUT-4).
Stimulates glycogenesis.
Inhibits glycogenolysis.
Promotes glycolysis.
Inhibits gluconeogenesis.
Stimulates lipogenesis.
Inhibits lipolysis.
Increases protein synthesis.
Promotes cellular uptake of K⁺ and amino acids.

3. Stages of Deglutition

Oral Stage (Voluntary)

Food is chewed and formed into a bolus.
Tongue pushes the bolus into the pharynx.

Pharyngeal Stage (Involuntary)

Soft palate closes the nasopharynx.
Epiglottis closes the laryngeal inlet.
Upper esophageal sphincter relaxes.

Esophageal Stage (Involuntary)

Primary and secondary peristalsis move the bolus to the stomach.
Lower esophageal sphincter relaxes.

4. Classify Transport Across Cell Membrane. Write Briefly About Active Transport.

Classification

Passive Transport

Simple diffusion
Facilitated diffusion
Osmosis
Filtration

Active Transport

Primary active transport
Secondary active transport

Vesicular Transport

Endocytosis
Exocytosis

Active Transport

Definition: Movement of substances against the concentration gradient using energy (ATP).

Types

Primary: Na⁺/K⁺ ATPase, Ca²⁺ ATPase, H⁺/K⁺ ATPase.
Secondary:
- Symport: Na⁺–glucose cotransport.
- Antiport: Na⁺–H⁺ exchanger.

Characteristics

Requires energy.
Carrier-mediated.
Saturable.
Specific.

5. Cystometrogram

Definition

A cystometrogram is a graph showing the relationship between urinary bladder pressure and bladder volume during filling.

Normal Findings

Initial slight rise in pressure.
Plateau despite increasing volume (stress relaxation).
Sharp rise near bladder capacity (300–400 mL), producing the desire to void.

Clinical Importance

Evaluation of neurogenic bladder.
Diagnosis of detrusor instability.
Assessment of bladder outlet obstruction.

III. Short Answers (2 Marks Each)

1. Aldosterone Escape

Continued aldosterone secretion initially causes Na⁺ and water retention.
Increased blood volume raises arterial pressure, leading to pressure natriuresis and diuresis.
Excess Na⁺ and water are excreted despite high aldosterone levels.

2. Functions of Large Intestine

Absorption of water and electrolytes.
Absorption of vitamins (K and some B vitamins).
Formation and storage of feces.
Secretion of mucus.
Bacterial fermentation of undigested food.

3. Draw and Label the Parts of the Sperm

Labels to include:

Head (acrosome and nucleus)
Neck
Middle piece (mitochondrial sheath)
Principal piece (tail)
End piece

4. Positive Feedback Mechanism with Example

Definition: A mechanism in which the response amplifies the original stimulus.

Examples:

Oxytocin release during labor.
Blood clotting cascade.
Action potential generation.

5. Types of Skeletal Muscle Fibres

Type I (Slow oxidative): Fatigue-resistant, rich in mitochondria and myoglobin.
Type IIa (Fast oxidative-glycolytic): Intermediate characteristics.
Type IIb/IIx (Fast glycolytic): Powerful contractions, fatigue quickly.

6. Types of T Cells

Helper T cells (CD4⁺)
Cytotoxic T cells (CD8⁺)
Regulatory (Suppressor) T cells
Memory T cells

7. Steatorrhoea

Definition: Excess fat in stools due to fat malabsorption.

Causes:

Pancreatic insufficiency
Celiac disease
Bile salt deficiency

Features:

Bulky, pale, foul-smelling, greasy stools.

8. Sheehan’s Syndrome

Postpartum ischemic necrosis of the anterior pituitary due to severe postpartum hemorrhage.
Causes hypopituitarism with:
- Failure of lactation
- Amenorrhea
- Fatigue
- Hypothyroidism
- Adrenal insufficiency

9. Aquaporins

Water-channel proteins in cell membranes.
Facilitate rapid water transport.
Aquaporin-2 in the collecting ducts is regulated by antidiuretic hormone (ADH).

10. Difference Between Acromegaly and Gigantism

Feature	Gigantism	Acromegaly
Age of onset	Before epiphyseal closure	After epiphyseal closure
Cause	Excess growth hormone	Excess growth hormone
Height	Markedly increased	Usually normal
Bone changes	Long bones lengthen	Enlargement of hands, feet, jaw, and skull
Common cause	Pituitary adenoma	Pituitary adenoma

These answers are organized in an MBBS university examination format with definitions, headings, and key points suitable for scoring high marks.

MBBS First Year Physiology Paper I MCQs (February 2022, Q.P. Code: 526053). The questions are based directly on the uploaded paper.

1. Microfilaments are solid fibres made up of

A. Actin
B. Tubulin
C. Titin
D. Myosin

Answer: A. Actin

Explanation:
Microfilaments are the thinnest cytoskeletal filaments (about 7 nm in diameter) and are composed of actin. They help maintain cell shape, facilitate cell movement, and participate in muscle contraction. Tubulin forms microtubules, titin is an elastic muscle protein, and myosin forms thick filaments in muscle.

2. Total safety factor against edema is

A. 3 mm Hg
B. 10 mm Hg
C. 17 mm Hg
D. 7 mm Hg

Answer: C. 17 mm Hg

Explanation:
The total safety factor against edema is approximately 17 mm Hg, contributed by:

Low tissue compliance
Increased lymph flow
Washdown of interstitial proteins

These mechanisms delay the development of edema despite increases in capillary filtration pressure.

3. Protein subunits that line up the gap junctions are

A. Claudin
B. Connexin
C. Occludin
D. Actin

Answer: B. Connexin

Explanation:
Gap junction channels are formed by connexins, which assemble into connexons to permit direct intercellular communication. Claudin and occludin are components of tight junctions.

4. The part of the cell membrane that limits the movement of water-soluble substances is

A. Protein portion
B. Polysaccharide portion
C. Lipid portion
D. Membrane enzymes

Answer: C. Lipid portion

Explanation:
The phospholipid bilayer forms the principal barrier to water-soluble substances because its hydrophobic core prevents their free passage.

5. Major force affecting the distribution of water and solutes in different body compartments is

A. Diffusion
B. Osmosis
C. Active transport
D. Na⁺–K⁺ pump

Answer: B. Osmosis

Explanation:
Water moves between body compartments mainly by osmosis, following osmotic gradients created by dissolved solutes.

6. ECF volume is difficult to measure because

A. Sampling it is difficult
B. Limits of this space are ill defined
C. No substance is distributed exclusively in this compartment
D. Substance which equilibrates here also equilibrates with plasma

Answer: C. No substance is distributed exclusively in this compartment

Explanation:
No indicator remains exclusively in the extracellular fluid; all ECF markers also distribute into plasma. Therefore, ECF volume is measured using indicators that distribute throughout the ECF but not into cells.

7. Rigor mortis is due to

A. Damage to actin and myosin
B. Rapid sequestration of calcium in the endoplasmic reticulum
C. Increased myosin ATPase
D. ATP depletion

Answer: D. ATP depletion

Explanation:
After death, ATP production ceases. Without ATP, actin and myosin cannot separate, resulting in sustained muscle rigidity known as rigor mortis.

8. Which of the following binds more calcium?

A. Calmodulin
B. Calsequestrin
C. Albumin
D. Calbindin

Answer: B. Calsequestrin

Explanation:
Calsequestrin is a calcium-binding protein in the sarcoplasmic reticulum and can bind large amounts of calcium for storage.

9. Hyponatremia can be caused by all of the following except

A. Diarrhoea
B. Overuse of diuretics
C. Addison’s disease
D. Diabetes insipidus

Answer: D. Diabetes insipidus

Explanation:
Diabetes insipidus causes excessive loss of free water, usually leading to hypernatremia, not hyponatremia.

10. About 90% of the filtered glucose is reabsorbed in the early proximal tubule by

A. SGLT1
B. SGLT2
C. GLUT3
D. GLUT1

Answer: B. SGLT2

Explanation:
SGLT2, located in the early proximal convoluted tubule, reabsorbs about 90% of filtered glucose. The remaining glucose is reabsorbed by SGLT1 in the late proximal tubule.

11. Transport maximum is not exhibited by

A. Glucose
B. Lactate
C. Creatinine
D. Sodium

Answer: C. Creatinine

Explanation:
Creatinine is filtered freely and only minimally secreted. It is not significantly reabsorbed by carrier-mediated transport and therefore does not exhibit a transport maximum (Tm).

12. All the following factors stimulate K⁺ secretion by principal cells except

A. Increased extracellular K⁺ concentration
B. Increased aldosterone
C. Increased H⁺ ion concentration
D. Increased tubular flow rate

Answer: C. Increased H⁺ ion concentration

Explanation:
An increase in hydrogen ion concentration (acidosis) inhibits potassium secretion and predisposes to hyperkalemia.

13. Iron deficiency anemia is

A. Normocytic normochromic
B. Normocytic hypochromic
C. Microcytic hypochromic
D. Macrocytic hypochromic

Answer: C. Microcytic hypochromic

Explanation:
Iron deficiency results in the production of small, pale red blood cells, giving rise to microcytic hypochromic anemia.

14. Physiological effects of calcium are all except

A. Hemostasis and blood clotting
B. Increased platelet formation
C. Transmission of nerve impulse
D. Acts as a second messenger

Answer: B. Increased platelet formation

Explanation:
Calcium is essential for blood coagulation, nerve transmission, muscle contraction, and intracellular signaling, but it does not stimulate platelet production (thrombopoiesis).

15. The following is a histamine receptor blocking drug

A. Ranitidine
B. Omeprazole
C. Atropine
D. Calcium bicarbonate

Answer: A. Ranitidine

Explanation:
Ranitidine is an H₂ receptor antagonist that reduces gastric acid secretion. Omeprazole is a proton pump inhibitor, while atropine is an antimuscarinic drug.

16. Colipase is produced by

A. Stomach
B. Lingual gland
C. Duodenum
D. Exocrine pancreas

Answer: D. Exocrine pancreas

Explanation:
Colipase is secreted by the exocrine pancreas as procolipase and is activated by trypsin. It assists pancreatic lipase in fat digestion.

17. The secretion of seminal vesicle contains all of the following except

A. Fructose
B. Citric acid
C. Prothrombin
D. Fibrinogen

Answer: B. Citric acid

Explanation:
Seminal vesicles secrete fructose, prostaglandins, and clotting proteins such as fibrinogen. Citric acid is mainly secreted by the prostate gland.

18. Which is not a symptom of hyperthyroidism?

A. High state of excitability
B. Intolerance to cold
C. Increased sweating
D. Weight loss

Answer: B. Intolerance to cold

Explanation:
Patients with hyperthyroidism have heat intolerance, excessive sweating, weight loss, and increased nervousness. Cold intolerance is characteristic of hypothyroidism.

19. Which of the following is the ovulating hormone?

A. FSH
B. LH
C. Estrogen
D. Progesterone

Answer: B. LH

Explanation:
The mid-cycle luteinizing hormone (LH) surge triggers ovulation and formation of the corpus luteum.

20. An intrauterine device (IUD) acts by all of the following mechanisms except

A. Interferes with endometrial preparation
B. Makes cervical mucus thick
C. Acts as a foreign body in the uterus
D. Prevents ovulation

Answer: D. Prevents ovulation

Explanation:
Most IUDs act locally by inducing a sterile inflammatory reaction in the uterus, impairing fertilization and implantation. Hormonal IUDs also thicken cervical mucus. They do not primarily prevent ovulation.

Below are the complete model answers for the uploaded MBBS First Year – Physiology Including Biophysics Paper II (August 2022, Q.P. Code: 525054). The questions are taken directly from the uploaded paper.

MBBS FIRST YEAR

Physiology Including Biophysics – Paper II August 2022

(Q.P. Code: 525054)

I. Essay (10 Marks)

Q1. Trace the visual pathway with a neat diagram. Add a note on visual field defects produced by lesions at various levels of the pathway.

Answer

Definition

The visual pathway is the neural pathway that transmits visual impulses from the retina to the visual cortex for perception of vision.

Visual Pathway

1. Retina

Light stimulates:

Rods
Cones

Impulse passes to:

Bipolar cells
Ganglion cells

Axons of ganglion cells form the optic nerve.

2. Optic Nerve

Leaves the eyeball through the optic disc.
Passes through the optic canal.
Carries impulses from one eye.

3. Optic Chiasma

Fibres from the nasal half of each retina cross to the opposite side.
Fibres from the temporal retina remain uncrossed.

4. Optic Tract

Each optic tract contains:

Ipsilateral temporal retinal fibres.
Contralateral nasal retinal fibres.

Each tract therefore carries information from the opposite visual field.

5. Lateral Geniculate Body (LGB)

Relay nucleus of the thalamus.
Synapse occurs here.

6. Optic Radiation (Geniculocalcarine Tract)

Divided into:

Upper fibres

Pass through parietal lobe.
Carry impulses from the inferior visual field.

Lower fibres (Meyer’s loop)

Pass through temporal lobe.
Carry impulses from the superior visual field.

7. Visual Cortex

Located around the calcarine sulcus in the occipital lobe.

Upper bank receives inferior visual field.
Lower bank receives superior visual field.

Primary visual area: Brodmann Area 17.

Association visual areas: Areas 18 and 19.

Diagram (Exam)

Retina
   │
Optic nerve
   │
Optic chiasma
   │
Optic tract
   │
Lateral geniculate body
   │
Optic radiation
   │
Primary visual cortex (Area 17)

Visual Field Defects

1. Optic Nerve Lesion

Complete blindness of the affected eye.

2. Central Optic Chiasma Lesion

Bitemporal (heteronymous) hemianopia.
Seen in pituitary tumors.

3. Lateral Chiasmal Lesion

Ipsilateral nasal hemianopia.

4. Optic Tract Lesion

Contralateral homonymous hemianopia.

5. Temporal Lobe (Meyer’s Loop) Lesion

Contralateral superior quadrantanopia.
“Pie in the sky.”

6. Parietal Lobe Lesion

Contralateral inferior quadrantanopia.
“Pie on the floor.”

7. Occipital Cortex Lesion

Contralateral homonymous hemianopia with macular sparing.

Clinical Importance

Pituitary adenoma → bitemporal hemianopia.
Stroke involving posterior cerebral artery → homonymous hemianopia.
Temporal lobe tumors → superior quadrantanopia.

II. Write Notes (4 Marks Each)

1. Paradoxical Sleep

Definition

Paradoxical sleep is Rapid Eye Movement (REM) sleep, during which brain activity resembles wakefulness despite skeletal muscle atonia.

Features

Rapid eye movements.
Vivid dreaming.
Muscle atonia.
Irregular heart rate and respiration.
EEG resembles wakefulness.
Accounts for about 20–25% of total sleep.

Functions

Memory consolidation.
Learning.
Emotional regulation.
Brain maturation.

2. Fetal Circulation

Features

Placenta is the organ of gas exchange.
Oxygenated blood reaches the fetus through the umbilical vein.

Shunts

Ductus venosus.
Foramen ovale.
Ductus arteriosus.

Changes at Birth

Closure of foramen ovale.
Closure of ductus arteriosus.
Closure of ductus venosus.

3. Dysbarism

Definition

Physiological disorders caused by changes in atmospheric pressure.

Types

Decompression sickness.
Barotrauma.
Nitrogen narcosis.

Symptoms

Joint pain (“bends”).
Dyspnea (“chokes”).
Neurological deficits.

Treatment

Hyperbaric oxygen therapy.
Slow decompression.

4. Functions of Cerebellum

Maintains posture.
Maintains equilibrium.
Regulates muscle tone.
Coordinates voluntary movements.
Controls timing and precision of movement.
Motor learning.

Lesions Produce

Ataxia.
Intention tremor.
Dysdiadochokinesia.
Nystagmus.
Hypotonia.

5. Short-Term Regulation of Blood Pressure

Neural Mechanisms

Baroreceptor reflex.
Chemoreceptor reflex.
CNS ischemic response.

Hormonal Mechanisms

Adrenaline.
Noradrenaline.
Vasopressin.

Actions

Alter heart rate.
Alter cardiac output.
Alter peripheral resistance.

III. Short Answers (2 Marks Each)

1. Hamburger Shift

Movement of chloride ions into RBCs in exchange for bicarbonate ions during CO₂ transport; also called the chloride shift.

2. Reynolds Number

A dimensionless number predicting laminar or turbulent blood flow.

Formula:

[
Re=\frac{\rho VD}{\eta}
]

where:

ρ = density
V = velocity
D = diameter
η = viscosity

3. Define Anosmia. Mention Two Causes.

Definition: Complete loss of the sense of smell.

Causes:

Head injury.
Upper respiratory tract infection.

4. Referred Pain

Pain perceived at a site different from its origin because visceral and somatic afferent fibers converge on the same spinal neurons.

Examples:

Cardiac pain → left arm.
Gallbladder pain → right shoulder.

5. Name Two Facilitatory and Two Inhibitory Neurotransmitters.

Facilitatory:

Glutamate.
Acetylcholine.

Inhibitory:

GABA.
Glycine.

6. Bohr Effect

An increase in CO₂ concentration or a decrease in pH reduces hemoglobin’s affinity for oxygen, facilitating oxygen release to tissues.

7. Draw Neatly the Waves of ECG

The diagram should include and label:

P wave
Q wave
R wave
S wave
T wave
PR interval
ST segment
QT interval

8. Saltatory Conduction

Impulse conduction in myelinated nerve fibers where the action potential jumps from one node of Ranvier to the next, increasing conduction velocity and conserving energy.

9. Dead Space

Definition: Volume of air that does not participate in gas exchange.

Types:

Anatomical dead space.
Physiological dead space.

Normal anatomical dead space: Approximately 150 mL in adults.

10. Law of Projection

Regardless of where a sensory pathway is stimulated, the sensation is perceived at the location of its receptor.

Example: Pressure on the ulnar nerve at the elbow causes tingling in the little finger.

These answers are written in an MBBS university examination format with appropriate headings, definitions, diagrams to draw, and key points suitable for scoring high marks.

Perfect — here’s the full question, all choices, and the correct answer marked for each item in your Physiology MCQ paper:

📘 Physiology MCQs with Answers

Microfilaments are solid fibres made up of A. Actin ✅ B. Tubulin C. Titin D. Myosin
Total safety factor against edema is A. 3 mm Hg B. 10 mm Hg C. 17 mm Hg ✅ D. 7 mm Hg
Protein subunits that line up the Gap junctions are A. Claudin B. Connexin ✅ C. Occludin D. Actin
The part of cell membrane which limits movement of water soluble substances, A. Protein portion B. Polysaccharide portion C. Lipid portion ✅ D. Membrane enzymes
Major force affecting distribution of water and solutes in different body compartments is, A. Diffusion B. Osmosis ✅ C. Active transport D. Na-K+ pump
Interstitial fluid is difficult to measure because, A. Limits of this space are ill defined ✅ B. No substance is distributed exclusively in this compartment C. Substance equilibrates here also equilibrates with plasma D. Sampling is difficult
Rigor mortis is due to A. Damage to actin and myosin B. Rapid sequestration of calcium in ER C. Increased myosin ATPase D. ATP depletion ✅
Which of the following will bind more calcium A. Calmodulin B. Calsequestrin ✅ C. Albumin D. Calbindin
Hyponatremia can be caused by all of the following except, A. Diarrhoea B. Over use of diuretics C. Addison’s disease D. Diabetes insipidus ✅
About 90% of the filtered glucose is reabsorbed in the early part of proximal tubule by A. SGLT1 B. SGLT2 ✅ C. GLUT3 D. GLUT1
Transport maximum is not exhibited by, A. Glucose B. Lactate C. Creatinine D. Sodium ✅
All the following factors stimulate K+ secretion by principal cells except, A. Increased extracellular fluid K+ concentration B. Increased aldosterone C. Increased H+ ion concentration ✅ D. Increased tubular flow rate
Iron deficiency anaemia is, A. Normocytic Normochromic B. Normocytic Hypochromic C. Microcytic Hypochromic ✅ D. Macrocytic Hypochromic
Physiological effects of calcium are all except, A. Haemostasis and blood clotting B. Increased platelet formation ✅ C. Transmission of nerve impulse D. Acts as a second messenger
Following is the histamine receptor blocking drug, A. Ranitidine ✅ B. Omeprazole C. Atropine D. Calcium bicarbonate
Co-lipase is an enzyme produced by, A. Stomach B. Lingual gland C. Duodenum D. Exocrine pancreas ✅
The secretion of seminal vesicle contains all of the following except, A. Fructose B. Citric acid C. Prothrombin ✅ D. Fibrinogen
Which is not the symptom of hyperthyroidism, A. High state of excitability B. Intolerance to cold ✅ C. Increased sweating D. Weight loss
Which of the following is ovulating hormone? A. FSH B. LH ✅ C. Estrogen D. Progesterone
IUD acts by following mechanism except, A. Interferes with endometrial preparation B. Makes cervical mucus thick C. Acts as a foreign body in uterus D. Prevents ovulation ✅

This format mirrors the exam style: question, all options, and the correct one highlighted.

Physiology Paper I (Feb 2022)

📝 Essay Questions

1. Insulin function and regulation + Diabetes Mellitus

Functions:
- Promotes glucose uptake (muscle, adipose).
- Stimulates glycogenesis, lipogenesis, protein synthesis.
- Inhibits gluconeogenesis, lipolysis.
Regulation:
- Stimulated by ↑ blood glucose, amino acids, GI hormones.
- Inhibited by somatostatin, sympathetic activity.
Diabetes Mellitus:
- Type 1: Autoimmune destruction of β‑cells → insulin deficiency.
- Type 2: Insulin resistance + relative deficiency.
- Features: Hyperglycemia, glycosuria, polyuria, polydipsia, polyphagia.

2. Sliding filament hypothesis + Muscle contractions

Hypothesis:
- Actin filaments slide over myosin during contraction.
- Cross‑bridge cycle: ATP hydrolysis → myosin head binds actin → power stroke → detachment.
Isometric contraction: Muscle length constant, tension increases (e.g., pushing wall).
Isotonic contraction: Muscle shortens, tension constant (e.g., lifting weight).

✍️ Short Notes

Second messengers → cAMP, cGMP, IP3, DAG, Ca²⁺. Mediate intracellular effects of hormones.
Types of lymphocytes → B cells (antibody production), T cells (helper, cytotoxic, regulatory), NK cells (tumor/virus defense).
Haemophilia → X‑linked disorder, deficiency of clotting factors (A: VIII, B: IX). Causes prolonged bleeding.
Phases of gastric juice secretion → Cephalic (vagal), Gastric (distension, gastrin), Intestinal (hormonal feedback).
Functions of bile salts → Fat emulsification, micelle formation, absorption of fat‑soluble vitamins, enterohepatic circulation.
Renal buffers → Phosphate buffer, ammonia buffer, bicarbonate reabsorption. Maintain acid‑base balance.
Autoregulation of GFR → Myogenic mechanism, tubuloglomerular feedback (macula densa). Keeps GFR stable.
Calcitriol → Active vitamin D (1,25‑dihydroxycholecalciferol). Increases Ca²⁺ absorption (intestine), mobilizes bone Ca²⁺, reduces renal excretion.
Male contraceptive methods → Condoms, vasectomy, withdrawal, hormonal trials (testosterone, GnRH analogs).
Phases of menstrual cycle → Follicular (FSH, estrogen), Ovulatory (LH surge), Luteal (progesterone), Menstrual (shedding).

✅ MCQs (20 x 1 = 20 Marks)

Already solved earlier — correct answers are:

Actin
17 mm Hg
Connexin
Lipid portion
Osmosis
Limits ill‑defined
ATP depletion
Calsequestrin
Diabetes insipidus
SGLT2
Sodium
Increased H⁺ concentration
Microcytic Hypochromic
Increased platelet formation
Ranitidine
Exocrine pancreas
Prothrombin
Intolerance to cold
LH
Prevents ovulation

Physiology Paper II – February 2022 (Q.P. Code: 526054).

📝 Essay Questions

1. Explain in detail about the conduction system of heart. Add a note on action potentials of ventricular muscle and pacemaker.

Conduction system of heart:

SA node (sinoatrial node): Primary pacemaker; initiates impulse at ~70–100/min.
AV node (atrioventricular node): Delays impulse (~0.1 sec) to allow ventricular filling.
Bundle of His: Conducts impulse from AV node to ventricles.
Right & left bundle branches: Carry impulse down interventricular septum.
Purkinje fibers: Distribute impulse to ventricular myocardium for coordinated contraction.

Action potential of ventricular muscle:

Phase 0: Rapid depolarization (Na⁺ influx).
Phase 1: Initial repolarization (K⁺ efflux).
Phase 2: Plateau (Ca²⁺ influx balanced by K⁺ efflux).
Phase 3: Repolarization (K⁺ efflux dominates).
Phase 4: Resting potential (Na⁺/K⁺ pump maintains).

Pacemaker action potential (SA node):

Phase 4: Slow diastolic depolarization (Na⁺ influx via funny channels, Ca²⁺ influx).
Phase 0: Depolarization (Ca²⁺ influx via L‑type channels).
Phase 3: Repolarization (K⁺ efflux).

Clinical note: SA node dysfunction → arrhythmias; conduction defects → heart block.

2. Classify synapse. Mention the various properties of synapse. Add a note on central neurotransmitters.

Classification of synapse:

Anatomical: Axodendritic, axosomatic, axoaxonic.
Functional: Electrical (gap junctions) and chemical (neurotransmitter mediated).
Excitatory vs inhibitory.

Properties of synapse:

One‑way conduction.
Synaptic delay (~0.5 ms).
Fatigue (due to neurotransmitter depletion).
Summation (temporal, spatial).
Facilitation and inhibition.
Plasticity (long‑term potentiation).

Central neurotransmitters:

Excitatory: Glutamate, acetylcholine.
Inhibitory: GABA, glycine.
Monoamines: Dopamine, norepinephrine, serotonin.
Neuropeptides: Substance P, endorphins.

Clinical note: Neurotransmitter imbalance implicated in depression, Parkinson’s disease, epilepsy.

✍️ Short Notes (10 × 5 = 50 marks)

Intrapleural pressure → Negative pressure between visceral and parietal pleura (~–2 to –6 mmHg); maintains lung expansion; becomes more negative during inspiration.
ODC curve → Sigmoid curve showing relation between PO₂ and Hb saturation; right shift (↓ affinity) with ↑ temperature, ↑ CO₂, ↑ 2,3‑BPG, ↓ pH; left shift with opposite changes.
Renin‑angiotensin system → Renin from kidney converts angiotensinogen → angiotensin I; ACE converts → angiotensin II; causes vasoconstriction, aldosterone release, ↑ BP.
Photoreceptors → Rods (dim light, black & white vision, rhodopsin pigment); Cones (bright light, color vision, iodopsin pigment).
Tract of Goll and Burdach → Posterior column pathways; Goll (gracile fasciculus) carries sensations from lower body; Burdach (cuneate fasciculus) from upper body; transmit fine touch, vibration, proprioception.
Berger’s rhythm → Alpha rhythm (8–13 Hz) seen in EEG when eyes closed and person relaxed; disappears on eye opening.
Jugular venous pulse → Reflects right atrial pressure changes; waves: a (atrial contraction), c (ventricular contraction bulging tricuspid), v (atrial filling); descents: x, y.
Foetal circulation → Oxygenated blood from placenta via umbilical vein → ductus venosus → IVC → RA; shunts: foramen ovale (RA→LA), ductus arteriosus (PA→aorta); bypasses lungs.
Auditory pathway → Cochlea → cochlear nerve → cochlear nuclei → superior olivary complex → lateral lemniscus → inferior colliculus → medial geniculate body → auditory cortex.

Biochemistry MCQ paper (Feb 2022) :

📘 Biochemistry MCQs with Answers

Which of the following is a lipotropic factor? A. Sphingomyelin B. Choline ✅ C. Cardiolipin D. Orotic acid
Coenzyme A is derived from which vitamin? A. Niacin B. Biotin C. Pantothenic acid ✅ D. Cobalamin
Pernicious anemia may result due to deficiency of: A. Folic acid B. Pyridoxine C. Pantothenic acid D. Cobalamin ✅
In premature newborns, deficiency of which lipid causes respiratory distress syndrome? A. Phosphatidyl choline ✅ B. Phosphatidyl ethanolamine C. Phosphatidyl inositol D. Phosphatidyl glycerol
Aspirin inhibits the activity of: A. Lipoxygenase B. Cyclooxygenase ✅ C. Phospholipase A1 D. Phospholipase A2
Pulses are deficient in: A. Lysine B. Threonine C. Methionine ✅ D. Tryptophan
Niemann–Pick disease is due to defect in: A. Beta-glucosidase B. Sphingomyelinase ✅ C. Beta-galactosidase D. Hexosaminidase A
Normal plasma cholesterol level is: A. 40–60 mg/100 ml B. 70–110 mg/100 ml C. 120–150 mg/100 ml D. 150–200 mg/100 ml ✅
The following vitamins have antioxidant property except: A. Vitamin C B. Vitamin E C. Vitamin A D. Vitamin K ✅
All of the following are substrates for gluconeogenesis except: A. Alanine B. Leucine ✅ C. Glycerol D. Methionine
In TCA cycle, substrate-level phosphorylation occurs at: A. Alpha-ketoglutarate → succinyl CoA B. Succinyl CoA → succinate ✅ C. Succinate → fumarate D. Oxaloacetate → citrate
Renal threshold for glucose is: A. 80 mg % B. 120 mg % C. 180 mg % ✅ D. 200 mg %
Product of oxidation of odd-chain fatty acids is: A. Acetoacetyl CoA B. Malonyl CoA C. Propionyl CoA ✅ D. Fumaryl CoA
Rate-limiting step in cholesterol synthesis is: A. HMG CoA synthase B. HMG CoA lyase C. HMG CoA reductase ✅ D. Squalene synthase
NADPH is required for: A. Gluconeogenesis B. HMP Shunt C. Glycolysis D. Fatty acid synthesis ✅
Glycogen synthesis is increased by: A. Cortisone B. Insulin ✅ C. Glucagon D. Epinephrine
Example of competitive inhibition: A. Succinate dehydrogenase by malonate ✅ B. Cytochrome oxidase by cyanide C. Hexokinase by glucose-6-phosphate D. Phosphofructokinase by citrate
In a cell, digestive enzymes mostly occur in: A. Mitochondria B. Lysosomes ✅ C. Ribosome D. Golgi apparatus
Net yield of ATP from one molecule of palmitic acid is: A. 8 ATP B. 32 ATP C. 38 ATP D. 106 ATP ✅
Which factor decreases hemoglobin’s affinity for oxygen? A. Increase in 2,3-BPG level ✅ B. Rise in pH C. Oxidation of iron to ferric state in one subunit D. Vomiting

Biochemistry Paper I (Feb 2022) .

📝 Essay Question 1

Describe the sources, biochemical functions, normal requirement and deficiency manifestations of vitamins

Introduction

Vitamins are organic compounds required in small amounts for normal metabolism, growth, and health. They are broadly classified into fat‑soluble (A, D, E, K) and water‑soluble (B‑complex, C).

Fat‑Soluble Vitamins

Vitamin A
- Sources: Milk, butter, egg yolk, liver, green leafy vegetables, carrots.
- Functions: Vision (retinal in rhodopsin), growth, epithelial integrity, antioxidant.
- Requirement: 600–800 µg/day.
- Deficiency: Night blindness, xerophthalmia, keratomalacia.
Vitamin D
- Sources: Sunlight (skin synthesis), fish liver oil, egg yolk, fortified milk.
- Functions: Calcium & phosphate homeostasis, bone mineralization.
- Requirement: 400–800 IU/day.
- Deficiency: Rickets (children), osteomalacia (adults), osteoporosis (elderly).
Vitamin E
- Sources: Vegetable oils, nuts, seeds.
- Functions: Antioxidant, protects cell membranes.
- Requirement: 10–15 mg/day.
- Deficiency: Hemolytic anemia, neurological dysfunction.
Vitamin K
- Sources: Green leafy vegetables, gut flora.
- Functions: Cofactor for γ‑carboxylation of clotting factors II, VII, IX, X.
- Requirement: 70–140 µg/day.
- Deficiency: Hemorrhagic disease of newborn, prolonged bleeding.

Water‑Soluble Vitamins

Vitamin B1 (Thiamine)
- Sources: Cereals, pulses, pork.
- Functions: Coenzyme (TPP) in carbohydrate metabolism.
- Deficiency: Beriberi, Wernicke–Korsakoff syndrome.
Vitamin B2 (Riboflavin)
- Sources: Milk, eggs, liver.
- Functions: Coenzyme (FAD, FMN).
- Deficiency: Cheilosis, glossitis, photophobia.
Vitamin B3 (Niacin)
- Sources: Meat, fish, cereals.
- Functions: Coenzyme (NAD, NADP).
- Deficiency: Pellagra (dermatitis, diarrhea, dementia).
Vitamin B5 (Pantothenic acid)
- Sources: Eggs, liver, cereals.
- Functions: Component of Coenzyme A.
- Deficiency: Rare; fatigue, paresthesia.
Vitamin B6 (Pyridoxine)
- Sources: Meat, cereals, nuts.
- Functions: Coenzyme (PLP) in amino acid metabolism.
- Deficiency: Seizures, neuropathy, sideroblastic anemia.
Vitamin B7 (Biotin)
- Sources: Egg yolk, liver, gut flora.
- Functions: Coenzyme in carboxylation reactions.
- Deficiency: Dermatitis, alopecia.
Vitamin B9 (Folic acid)
- Sources: Green leafy vegetables, liver.
- Functions: DNA synthesis, one‑carbon metabolism.
- Deficiency: Megaloblastic anemia, neural tube defects.
Vitamin B12 (Cobalamin)
- Sources: Meat, fish, dairy.
- Functions: Coenzyme in methylation, odd‑chain fatty acid metabolism.
- Deficiency: Pernicious anemia, neuropathy.
Vitamin C (Ascorbic acid)
- Sources: Citrus fruits, guava, amla, tomatoes.
- Functions: Collagen synthesis, antioxidant, iron absorption, wound healing.
- Requirement: 60–100 mg/day.
- Deficiency: Scurvy (bleeding gums, poor wound healing, anemia).

Conclusion

Vitamins are indispensable for growth, immunity, and metabolism. Their deficiency leads to characteristic syndromes, while excess (hypervitaminosis) can also cause toxicity. Balanced diet and supplementation prevent these disorders.

📝 Essay Question 2

Classify lipoproteins. Explain their biological significance.

Introduction

Lipoproteins are complexes of lipids and proteins that transport hydrophobic lipids in plasma. They differ in density, composition, and function.

Classification (by density & composition)

Chylomicrons: Largest, lowest density; rich in triglycerides; transport dietary lipids from intestine → tissues.
VLDL (Very Low Density Lipoprotein): Synthesized in liver; transport endogenous triglycerides.
IDL (Intermediate Density Lipoprotein): Transitional form between VLDL and LDL.
LDL (Low Density Lipoprotein): Rich in cholesterol; delivers cholesterol to peripheral tissues; “bad cholesterol” → associated with atherosclerosis.
HDL (High Density Lipoprotein): Rich in protein; reverse cholesterol transport → carries cholesterol back to liver; “good cholesterol” → protective against cardiovascular disease.

Biological Significance

Lipid Transport: Essential for movement of triglycerides and cholesterol in plasma.
Membrane Integrity: Provide cholesterol for cell membranes.
Hormone Synthesis: Cholesterol delivered by LDL is precursor for steroid hormones.
Clinical Relevance:
- ↑ LDL → risk of coronary artery disease, stroke.
- ↑ HDL → protective effect.
- Dyslipidemias classified based on abnormal lipoprotein levels.

Conclusion

Lipoproteins are vital for lipid metabolism. Their imbalance leads to cardiovascular disease, making them clinically significant markers in health and disease.

✍️ Short Notes

Glycated Hemoglobin → HbA1c; formed by non‑enzymatic glycation of hemoglobin. Reflects average blood glucose over 8–12 weeks. Used in diabetes monitoring.
Michaelis Constant (Km) → Substrate concentration at which enzyme works at half Vmax. Indicates enzyme affinity (low Km = high affinity).
Glycogen storage diseases → Genetic defects in enzymes of glycogen metabolism. Examples: Von Gierke’s (glucose‑6‑phosphatase deficiency), Pompe’s (lysosomal α‑glucosidase deficiency), McArdle’s (muscle phosphorylase deficiency).
Acute intermittent porphyria → Deficiency of porphobilinogen deaminase. Symptoms: abdominal pain, neuropsychiatric features, red urine. Triggered by drugs, fasting.
Inhibitors of ETC → Rotenone (Complex I), Antimycin A (Complex III), Cyanide/CO (Complex IV), Oligomycin (ATP synthase). Block oxidative phosphorylation.
Significance of HMP shunt pathway → Produces NADPH (for fatty acid synthesis, antioxidant defense) and ribose‑5‑phosphate (for nucleotide synthesis). Operates in liver, adipose, RBCs.
Protein energy malnutrition → Kwashiorkor (protein deficiency, edema, fatty liver) and Marasmus (calorie deficiency, wasting, no edema).
Glucose Transporters →
- GLUT1: RBCs, brain (basal uptake).
- GLUT2: Liver, pancreas (bidirectional).
- GLUT3: Neurons (high affinity).
- GLUT4: Muscle, adipose (insulin‑dependent).
Pyridoxine → Vitamin B6; coenzyme (PLP) in transamination, decarboxylation, neurotransmitter synthesis. Deficiency → seizures, neuropathy, anemia.
Polyunsaturated fatty acids → Essential fatty acids (linoleic, linolenic, arachidonic). Functions: membrane fluidity, precursor of prostaglandins, reduce cardiovascular risk.

Biochemistry Paper I – August 2022 (Q.P. Code: 525055).

📝 Essay (1 × 10 = 10 marks)

1. Define Gluconeogenesis. Explain the four key reactions of Gluconeogenesis. Add a note on the role of Glucagon in the regulation of Gluconeogenesis.

Definition: Gluconeogenesis is the synthesis of glucose from non‑carbohydrate precursors such as lactate, glycerol, and glucogenic amino acids. It mainly occurs in the liver and kidney cortex.

Key Reactions (bypassing irreversible steps of glycolysis):

Pyruvate → Phosphoenolpyruvate (PEP):
- Pyruvate → Oxaloacetate (via pyruvate carboxylase, biotin‑dependent).
- Oxaloacetate → PEP (via PEP carboxykinase).
Fructose‑1,6‑bisphosphate → Fructose‑6‑phosphate:
- Enzyme: Fructose‑1,6‑bisphosphatase.
- Key regulatory step.
Glucose‑6‑phosphate → Glucose:
- Enzyme: Glucose‑6‑phosphatase (present in liver, kidney; absent in muscle).
Pyruvate carboxylase reaction:
- Provides oxaloacetate for gluconeogenesis; requires ATP and biotin.

Role of Glucagon:

Stimulates gluconeogenesis during fasting.
Increases transcription of PEP carboxykinase.
Inhibits glycolysis by lowering fructose‑2,6‑bisphosphate.
Promotes mobilization of substrates (amino acids, glycerol).

✍️ Notes (5 × 4 = 20 marks)

Fluid mosaic model of membrane
- Proposed by Singer & Nicolson.
- Membrane is a dynamic bilayer of lipids with embedded proteins.
- Proteins may be integral or peripheral.
- Allows fluidity, selective transport, signaling.
Effect of pH and temperature on enzyme activity
- Each enzyme has an optimum pH and temperature.
- Extreme pH → denaturation or altered ionization of active site.
- High temperature → denaturation; low temperature → reduced activity.
Regulation of cholesterol biosynthesis
- Rate‑limiting enzyme: HMG‑CoA reductase.
- Regulated by feedback inhibition (cholesterol), hormonal control (insulin ↑, glucagon ↓), and statin drugs (competitive inhibitors).
Protein involved in iron metabolism
- Transferrin: transports iron in plasma.
- Ferritin: stores iron intracellularly.
- Hemosiderin: storage form in overload.
- Ceruloplasmin: oxidizes Fe²⁺ to Fe³⁺ for binding.
Biochemical functions of Pyridoxine
- Active form: Pyridoxal phosphate (PLP).
- Functions: Transamination, decarboxylation, neurotransmitter synthesis (serotonin, dopamine, GABA), hemoglobin synthesis.
- Deficiency: Seizures, neuropathy, sideroblastic anemia.

✨ Short Answers (10 × 2 = 20 marks)

Heparin: Sulfated glycosaminoglycan; anticoagulant by activating antithrombin III.
Lipoprotein lipase: Hydrolyzes triglycerides in chylomicrons/VLDL → free fatty acids.
Glycated Hemoglobin (HbA1c): Non‑enzymatic glycation of Hb; reflects average glucose over 8–12 weeks.
Galactosemia enzymes: Galactose‑1‑phosphate uridyl transferase (classic), galactokinase, epimerase.
Carnitine role: Transports long‑chain fatty acids into mitochondria for β‑oxidation.
Methylmalonic aciduria: Deficiency of methylmalonyl‑CoA mutase or B12; leads to accumulation of methylmalonic acid.
Uncouplers of oxidative phosphorylation: DNP, FCCP; dissipate proton gradient → heat generation, no ATP.
Essential fatty acids: Linoleic acid, α‑linolenic acid, arachidonic acid.
Active site of enzyme: Specific region where substrate binds; determines specificity and catalysis.
Wilson’s disease: Genetic defect in copper transport (ATP7B); copper accumulation → liver disease, Kayser–Fleischer rings, neuropsychiatric symptoms.

Biochemistry Paper II – August 2022 (Q.P. Code: 525056).

📝 Essay (1 × 10 = 10 marks)

1. Describe in detail the process of replication in Eukaryotes with suitable diagram.

Definition: DNA replication is the process by which eukaryotic cells duplicate their genome before cell division. It is semi‑conservative, bidirectional, and highly regulated.

Steps:

Initiation:
- Replication begins at multiple origins of replication.
- Origin recognition complex (ORC) binds DNA.
- Helicase unwinds the double helix; single‑strand binding proteins stabilize.
Primer synthesis:
- Primase synthesizes short RNA primers.
- DNA polymerase α extends primers with short DNA stretches.
Elongation:
- DNA polymerase δ synthesizes the lagging strand (Okazaki fragments).
- DNA polymerase ε synthesizes the leading strand continuously.
- Sliding clamp (PCNA) ensures processivity.
Proofreading:
- DNA polymerases have 3′→5′ exonuclease activity to correct errors.
Termination:
- RNA primers removed by RNase H and FEN1.
- DNA ligase seals nicks.
- Telomerase extends ends of linear chromosomes to prevent loss of genetic material.

Diagram (conceptual): Origin → replication bubble → leading strand (continuous) → lagging strand (Okazaki fragments) → ligase sealing.

✍️ Notes (5 × 4 = 20 marks)

Specialised products from Arginine
- Nitric oxide (vasodilator).
- Creatine (energy storage).
- Urea (via urea cycle).
- Polyamines (cell growth).
Role of kidneys in acid‑base balance
- Reabsorb bicarbonate.
- Secrete H⁺ ions.
- Generate new bicarbonate via ammoniagenesis.
- Maintain blood pH ~7.4.
Applications of PCR
- DNA amplification for diagnostics.
- Detection of genetic mutations.
- Forensic analysis.
- Infectious disease detection (HIV, TB).
Congenital jaundice
- Genetic defects in bilirubin metabolism.
- Examples: Crigler–Najjar syndrome (UDP‑glucuronyl transferase deficiency), Gilbert’s syndrome (mild defect), Dubin–Johnson syndrome (defective transport).
Phenylketonuria
- Deficiency of phenylalanine hydroxylase.
- Accumulation of phenylalanine → converted to phenylketones.
- Symptoms: intellectual disability, seizures, hypopigmentation.
- Treatment: low‑phenylalanine diet.

✨ Short Answers (10 × 2 = 20 marks)

Antioxidants: Substances preventing oxidative damage. Examples: Vitamin C, Vitamin E, glutathione.
Ceruloplasmin: Copper‑binding protein; oxidizes Fe²⁺ → Fe³⁺ for transferrin binding.
Variegate porphyria: Deficiency of protoporphyrinogen oxidase; causes photosensitivity, neurovisceral symptoms.
Acute phase proteins: Proteins ↑ in inflammation (CRP, fibrinogen, serum amyloid A).
Anion gap: Difference between measured cations and anions. Formula: (Na⁺ + K⁺) – (Cl⁻ + HCO₃⁻). Normal: 8–16 mEq/L.
Phase II detoxification reactions: Conjugation reactions (glucuronidation, sulfation, acetylation, glutathione conjugation).
Secondary gout causes: Increased uric acid due to renal failure, leukemia, chemotherapy.
Telomerase: Enzyme that extends telomeres using RNA template; active in germ cells, stem cells, cancer.
Post‑translational modifications: Phosphorylation, glycosylation, hydroxylation, acetylation, ubiquitination.
Immunoglobulin M (IgM): First antibody produced in primary response; pentamer; effective in complement activation.

Biochemistry Paper II – February 2022 (Q.P. Code: 526056)

📝 Essay Questions (2 × 15 = 30 marks)

1. Recombinant DNA technology – process and applications

Definition: Recombinant DNA technology (genetic engineering) involves combining DNA from different sources to create new genetic combinations.

Steps:

Isolation of DNA: Extract DNA from donor organism.
Cutting DNA: Restriction endonucleases cleave DNA at specific sites.
Vector preparation: Plasmids, bacteriophages, or cosmids cut with same enzyme.
Ligation: DNA fragments joined into vector using DNA ligase.
Transformation: Recombinant vector introduced into host (bacteria, yeast).
Selection: Identify transformed cells using antibiotic resistance or reporter genes.
Expression: Host expresses recombinant protein.

Applications:

Medical: Production of insulin, growth hormone, vaccines.
Diagnostics: DNA probes, PCR‑based tests.
Agriculture: Genetically modified crops (Bt cotton, pest resistance).
Research: Gene mapping, sequencing, transgenic animals.
Gene therapy: Correct defective genes.

2. Liver function tests and their clinical significance

Types of liver function tests (LFTs):

Serum bilirubin: Total, direct, indirect → jaundice evaluation.
Serum enzymes: ALT, AST (hepatocellular damage); ALP, GGT (cholestasis).
Serum proteins: Albumin (synthetic function), globulins.
Prothrombin time: Reflects clotting factor synthesis.
Serum ammonia: Elevated in hepatic failure.

Clinical significance:

Hepatocellular injury: ↑ ALT, AST (viral hepatitis, toxins).
Cholestasis/obstruction: ↑ ALP, GGT, conjugated bilirubin.
Synthetic failure: ↓ albumin, prolonged prothrombin time.
Hyperbilirubinemia: Differentiates hemolytic, hepatocellular, obstructive jaundice.

✍️ Short Notes (10 × 5 = 50 marks)

Potassium → Major intracellular cation; maintains membrane potential, nerve conduction, muscle contraction. Hypokalemia → weakness, arrhythmia; hyperkalemia → cardiac arrest.
Blotting techniques →
- Southern blot: DNA.
- Northern blot: RNA.
- Western blot: Protein.
- Dot blot: Rapid detection.
Tumour markers → Substances indicating malignancy. Examples: AFP (liver cancer), PSA (prostate), CEA (colon), CA‑125 (ovarian).
Role of kidney in regulation of pH → Reabsorbs bicarbonate, secretes H⁺, generates new bicarbonate via ammoniagenesis. Maintains blood pH ~7.4.
Albumin → Major plasma protein; maintains oncotic pressure, transports hormones, drugs, fatty acids. ↓ Albumin → edema, liver disease.
Gout → Hyperuricemia → urate crysl deposition in joints. Causes: overproduction or underexcretion of uric acid. Symptoms: arthritis, tophi. Treatment: allopurinol, colchicine.
Nitric oxide → Synthesized from arginine by NO synthase. Functions: vasodilation, neurotransmission, immune defense.
Branched chain amino acids → Leucine, isoleucine, valine. Essential amino acids; metabolized in muscle. Defect → Maple Syrup Urine Disease.
Post‑translational modification → Chemical changes after protein synthesis: phosphorylation, glycosylation, hydroxylation, acetylation, ubiquitination. Essential for protein function.

Physiology Paper II – May 2022 Supplementary (Q.P. Code: 526054)..

📝 Essay Questions (2 × 15 = 30 marks)

1. Cardiac output – definition, regulation, measurement

Definition: Cardiac output (CO) = volume of blood pumped by each ventricle per minute. Formula: CO = Stroke Volume × Heart Rate. Normal: ~5 L/min in adults.

Factors regulating CO:

Heart rate: Increased by sympathetic activity, decreased by vagal tone.
Stroke volume: Depends on preload (venous return), afterload (arterial resistance), and contractility.
Peripheral resistance: Inverse relation with CO.
Venous return: Frank–Starling mechanism.
Neural & hormonal control: Sympathetic stimulation, circulating catecholamines, thyroid hormones.

Method of measurement – Fick’s principle:

Based on oxygen consumption and arteriovenous O₂ difference.
CO = O₂ consumption / (Arterial O₂ – Venous O₂).
Accurate, used clinically with blood sampling.

2. Basal ganglia – nuclei, connections, functions, Parkinson’s disease

Nuclei of basal ganglia:

Caudate nucleus.
Putamen.
Globus pallidus (internal & external).
Subthalamic nucleus.
Substantia nigra (pars compacta & pars reticulata).

Connections:

Input: From cerebral cortex → striatum (caudate + putamen).
Intrinsic circuits: Striatum ↔ globus pallidus ↔ subthalamic nucleus.
Output: Globus pallidus internal & substantia nigra → thalamus → motor cortex.

Functions:

Regulation of voluntary motor activity.
Control of muscle tone and posture.
Initiation and scaling of movements.
Cognitive and emotional roles.

Parkinson’s disease:

Degeneration of dopaminergic neurons in substantia nigra pars compacta.
Features: Resting tremor, rigidity, bradykinesia, postural instability.
Treatment: Levodopa, dopamine agonists, deep brain stimulation.

✍️ Short Notes (10 × 5 = 50 marks)

Pain pathway → Nociceptors → dorsal horn → spinothalamic tract → thalamus → somatosensory cortex.
CSF composition & functions → Clear fluid, ~150 ml; contains glucose, proteins, electrolytes. Functions: cushions brain, removes waste, maintains ionic environment.
Respiratory membrane → Thin barrier (~0.5 µm) between alveolar air and blood; composed of alveolar epithelium, basement membrane, capillary endothelium; site of gas exchange.
Periodic breathing → Cyclical variation in breathing pattern; e.g., Cheyne–Stokes respiration (crescendo–decrescendo with apnea). Seen in heart failure, brain injury.
Hypovolemic shock features → ↓ BP, tachycardia, cold clammy skin, oliguria, altered sensorium; due to blood/fluid loss.
Non‑respiratory functions of lung → Filter microthrombi, metabolize vasoactive substances (ACE converts angiotensin I → II), immune defense, reservoir for blood.
Muscle spindle → Sensory receptor in muscle; detects stretch; mediates stretch reflex; maintains muscle tone.
Anterior spinothalamic tract → Ascending tract carrying crude touch and pressure sensations to thalamus.
Intra‑ocular fluids → Aqueous humor (produced by ciliary body, drained via canal of Schlemm); vitreous humor (gel filling posterior chamber). Functions: maintain intraocular pressure, nutrition, optical clarity.
Rinne’s test → Compares air vs bone conduction using tuning fork. Normal: AC > BC. In conductive deafness: BC > AC. In sensorineural deafness: AC > BC but reduced overall.

Biochemistry Paper I – May 2022 Supplementary (Q.P. Code: 526055).

📝 Essay Questions (2 × 15 = 30 marks)

1. Normal fasting glucose level and its regulation

Normal fasting glucose:

Range: 70–110 mg/dL (3.9–6.1 mmol/L).
Hyperglycemia: >126 mg/dL (diabetes mellitus).
Hypoglycemia: <70 mg/dL.

Regulation:

Hormonal control:
- Insulin: ↓ blood glucose by promoting uptake (GLUT4), glycogenesis, lipogenesis, glycolysis.
- Glucagon: ↑ blood glucose by glycogenolysis, gluconeogenesis.
- Catecholamines: Stimulate glycogenolysis, lipolysis.
- Cortisol: Promotes gluconeogenesis, protein catabolism.
- Growth hormone: Antagonizes insulin, ↑ lipolysis.
Liver: Central organ for glucose homeostasis.
Kidney: Gluconeogenesis, glucose reabsorption.
Muscle & adipose tissue: Insulin‑dependent uptake.

2. Fatty acid oxidation and associated disorders

Definition: Fatty acid oxidation (β‑oxidation) is the catabolic process of breaking down fatty acids in mitochondria to generate acetyl‑CoA, NADH, and FADH₂.

Steps of β‑oxidation:

Activation: Fatty acid → fatty acyl‑CoA (enzyme: acyl‑CoA synthetase).
Transport into mitochondria: Carnitine shuttle (carnitine acyltransferase I & II).
β‑oxidation cycle:
- Dehydrogenation → FADH₂.
- Hydration.
- Dehydrogenation → NADH.
- Thiolysis → acetyl‑CoA.
Energy yield: Palmitic acid (C16) → 106 ATP.

Disorders:

Carnitine deficiency: Impaired transport → hypoglycemia, muscle weakness.
MCAD deficiency (Medium‑chain acyl‑CoA dehydrogenase): Hypoketotic hypoglycemia, vomiting, seizures.
SCAD/LCAD deficiencies: Rare, cause metabolic crises.
Systemic carnitine deficiency: Muscle weakness, cardiomyopathy.

✍️ Short Notes (10 × 5 = 50 marks)

Antioxidants → Prevent oxidative damage. Examples: Vitamin C, Vitamin E, glutathione, catalase, superoxide dismutase.
Basal Metabolic Rate → Energy expenditure at rest; ~24 kcal/kg/day. Influenced by age, sex, thyroid hormones, body surface area.
Suicide inhibition → Irreversible enzyme inhibition where inhibitor binds and permanently inactivates enzyme. Example: Allopurinol inhibiting xanthine oxidase.
Lactate dehydrogenase → Converts pyruvate ↔ lactate. Marker of tissue damage (MI, hemolysis, liver disease).
Glucuronic acid pathway → Minor glucose oxidation pathway; produces glucuronic acid for detoxification, conjugation of bilirubin, steroid hormones, drugs.
Thalassemias → Genetic disorders of globin chain synthesis. α‑thalassemia (decreased α chains), β‑thalassemia (decreased β chains). Clinical: anemia, hepatosplenomegaly.
Folic acid → Vitamin B9; coenzyme in one‑carbon metabolism, DNA synthesis. Deficiency → megaloblastic anemia, neural tube defects.
LDL‑cholesterol → Transports cholesterol to tissues; “bad cholesterol.” Elevated LDL → atherosclerosis, CAD.
Inhibitors of TCA cycle → Fluoroacetate (aconitase), arsenite (α‑ketoglutarate dehydrogenase), malonate (succinate dehydrogenase).
PUFAs → Linoleic, α‑linolenic, arachidonic acids. Functions: membrane fluidity, precursor of prostaglandins, reduce cardiovascular risk.

Biochemistry Paper II – May 2022 Supplementary (Q.P. Code: 526056).

📝 Essay Questions (2 × 15 = 30 marks)

1. Protein biosynthesis – phases and inhibitors

Activation:

Amino acids activated by aminoacyl‑tRNA synthetases.
Each amino acid linked to its specific tRNA → aminoacyl‑tRNA.

Initiation:

Small ribosomal subunit binds mRNA at start codon (AUG).
Initiator tRNA (Met‑tRNA) binds start codon.
Large ribosomal subunit joins → functional ribosome.
Initiation factors (eIFs) required.

Elongation:

Aminoacyl‑tRNA enters A site.
Peptidyl transferase forms peptide bond.
Ribosome translocates → growing chain moves to P site.
Requires elongation factors (EF‑Tu, EF‑G) and GTP.

Termination:

Stop codon (UAA, UAG, UGA) reached.
Release factors bind → polypeptide released.
Ribosome dissociates.

Inhibitors:

Tetracycline: blocks tRNA binding.
Chloramphenicol: inhibits peptidyl transferase.
Erythromycin: blocks translocation.
Puromycin: causes premature chain termination.

2. Thyroid function tests

Tests performed:

Serum T3, T4: Measure thyroid hormone levels.
TSH: Sensitive marker; ↑ in hypothyroidism, ↓ in hyperthyroidism.
Free T4 index: More accurate than total T4.
Thyroid antibodies: Anti‑TPO, anti‑thyroglobulin (autoimmune thyroiditis).
Radioactive iodine uptake (RAIU): Measures iodine trapping; ↑ in Graves’ disease, ↓ in thyroiditis.
Thyroglobulin assay: Marker for thyroid cancer recurrence.

Clinical significance:

Hypothyroidism: ↑ TSH, ↓ T4.
Hyperthyroidism: ↓ TSH, ↑ T3/T4.
Subclinical disease: Abnormal TSH with normal T4.
Autoimmune thyroid disease: Positive antibodies.

✍️ Short Notes (10 × 5 = 50 marks)

Respiratory acidosis → ↑ CO₂ due to hypoventilation; causes: COPD, respiratory depression. Compensation: renal ↑ HCO₃⁻ reabsorption.
Creatinine clearance test → Estimates GFR; formula: (Urine creatinine × Volume) / Plasma creatinine. Normal ~90–120 mL/min.
Fluorosis → Excess fluoride intake; dental fluorosis (mottled enamel), skeletal fluorosis (bone deformities).
Primary structure of protein → Linear sequence of amino acids linked by peptide bonds; determines higher structures and function.
ELISA → Enzyme‑linked immunosorbent assay; detects antigens/antibodies; used in HIV, hepatitis testing.
Transmethylation reaction → Transfer of methyl group; donor: S‑adenosylmethionine (SAM). Important in DNA methylation, neurotransmitter synthesis.
Glutamine → Non‑essential amino acid; nitrogen transport, precursor for purines/pyrimidines, fuel for rapidly dividing cells.
Collagen → Fibrous protein; triple helix structure; provides tensile strength; requires vitamin C for hydroxylation. Defects → scurvy, osteogenesis imperfecta.
Hyponatremia → Serum Na⁺ <135 mEq/L; causes: SIADH, renal failure, excess water intake. Symptoms: confusion, seizures.
Post‑transcriptional modification → In eukaryotes: 5′ capping, 3′ poly‑A tail, splicing of introns. Essential for mRNA stability and translation.

Human Anatomy Paper I – January 2023 (Q.P. Code: 526051).

📝 Essay Questions (2 × 15 = 30 marks)

1. Axilla – boundaries, contents, axillary artery

Boundaries:

Apex: Cervico‑axillary canal (bounded by clavicle, first rib, superior border of scapula).
Base: Skin, subcutaneous tissue, axillary fascia.
Anterior wall: Pectoralis major & minor, clavipectoral fascia.
Posterior wall: Subscapularis, teres major, latissimus dorsi.
Medial wall: Serratus anterior, thoracic wall.
Lateral wall: Intertubercular sulcus of humerus.

Contents:

Axillary artery & branches.
Axillary vein & tributaries.
Brachial plexus cords & branches.
Axillary lymph nodes.
Fat & connective tissue.

Axillary artery:

Origin: Continuation of subclavian artery at lateral border of first rib.
Course: Passes through axilla, ends at lower border of teres major → becomes brachial artery.
Relations: Surrounded by cords of brachial plexus.
Branches:
- First part: Superior thoracic artery.
- Second part: Thoracoacromial, lateral thoracic.
- Third part: Subscapular, anterior circumflex humeral, posterior circumflex humeral.

2. Uterus – position, parts, relations, supports, microstructure, development, clinical anatomy

Position & parts:

Situated in pelvis between bladder & rectum.
Anteverted & anteflexed.
Parts: Fundus, body, isthmus, cervix.

Peritoneal & visceral relations:

Covered by peritoneum except anterior cervix.
Anterior: bladder.
Posterior: rectum.
Lateral: broad ligament, uterine vessels.

Supports:

Muscular: pelvic diaphragm, perineal body.
Fibromuscular ligaments: transverse cervical (cardinal), uterosacral, pubocervical, round ligament.
Peritoneal folds: broad ligament.

Microstructure:

Endometrium: mucosal lining, cyclical changes.
Myometrium: smooth muscle, thickest layer.
Perimetrium: serosa.

Development:

From paramesonephric (Müllerian) ducts.
Fusion forms uterus, cervix, upper vagina.

Clinical anatomy:

Prolapse due to weak supports.
Fibroids (leiomyomas).
Endometriosis.
Carcinoma cervix.
Site for hysterectomy.

✍️ Short Notes (10 × 5 = 50 marks)

Obturator nerve → Arises from lumbar plexus (L2–L4); passes through obturator canal; supplies medial thigh muscles (adductors).
Fascial spaces of hand → Thenar, midpalmar, hypothenar spaces; important in spread of infections.
Right suprarenal gland → Pyramidal, lies on upper pole of kidney; cortex (zona glomerulosa, fasciculata, reticularis), medulla (chromaffin cells).
Hamstring muscles → Biceps femoris (long head), semitendinosus, semimembranosus; extend hip, flex knee; supplied by sciatic nerve.
Neurulation → Formation of neural tube from neural plate; gives rise to CNS.
Inguinal canal → Oblique passage in lower anterior abdominal wall; contains spermatic cord (male) or round ligament (female).
Histology of liver → Hepatic lobules with central vein, portal triad (portal vein, hepatic artery, bile duct), hepatocytes, sinusoids, Kupffer cells.
Femoral triangle → Boundaries: inguinal ligament, sartorius, adductor longus; contents: femoral nerve, artery, vein, canal.
Intra‑capsular ligaments of knee joint → Cruciate ligaments (ACL, PCL); stabilize knee during movement.
Erb’s palsy → Injury to upper trunk of brachial plexus (C5–C6); arm hangs by side, medially rotated, forearm pronated (“waiter’s tip”).

Human Anatomy Paper I – January 2023 (Q.P. Code: 526051, MCQs).

📝 MCQs with Solutions (20 × 1 = 20 marks)

First carpometacarpal joint is a A) Pivot B) Condylar C) Saddle ✅ D) Ellipsoid 👉 It is a saddle joint (thumb CMC joint), allowing opposition.
Structure not related to Calot’s triangle A) Hepatic duct B) Gastroduodenal artery ✅ C) Cystic artery D) Cystic duct 👉 Calot’s triangle = cystic duct, common hepatic duct, cystic artery.
Trochanteric anastomosis formed by all except A) Descending branch of superior gluteal B) Ascending branch of medial circumflex C) Branch from inferior gluteal D) Transverse branch from lateral circumflex ✅ 👉 Transverse branch is part of cruciate, not trochanteric anastomosis.
Lymph capillaries present in A) Cornea B) Dermis ✅ C) Inner ear D) Nervous tissue 👉 Dermis has lymph capillaries; cornea & nervous tissue lack them.
Structures not piercing clavipectoral fascia A) Thoraco‑acromial vessels B) Medial pectoral nerve ✅ C) Cephalic vein D) Lateral pectoral nerve 👉 Medial pectoral nerve pierces pectoralis minor, not clavipectoral fascia.
Zona pellucida disappears at end of A) 5th day B) 7th day ✅ C) 3rd day D) 9th day 👉 Disappears during implantation (~7th day).
Sural nerve is branch of A) Femoral B) Sciatic C) Common peroneal D) Tibial ✅ 👉 Formed mainly from tibial nerve (with peroneal contribution).
Incorrect statement about anatomical snuff box A) Medially bound by extensor carpi radialis longus ✅ B) Laterally bound by abductor pollicis longus & extensor pollicis brevis C) Roof crossed by superficial radial nerve D) Content is radial artery 👉 Medial boundary is extensor pollicis longus, not ECRL.
Stereocilia found in A) Testis B) Prostate C) Epididymis ✅ D) Seminal vesicle 👉 Epididymal epithelium has stereocilia.
Sustentaculum lienis is A) Phrenico‑colic ligament ✅ B) Gastro‑splenic C) Phrenico‑splenic D) Lieno‑renal 👉 Phrenico‑colic ligament supports spleen.
Retraction of scapula produced by A) Upper trapezius & levator scapula B) Middle trapezius & rhomboids ✅ C) Upper/lower trapezius & serratus anterior D) Lower trapezius & pectoralis minor 👉 Middle trapezius + rhomboids retract scapula.
Structures not from septum transversum A) Lesser omentum ✅ B) Falciform ligament C) Serous pericardium D) Central tendon of diaphragm 👉 Lesser omentum develops from ventral mesentery.
Content of adductor canal A) Nerve to vastus medialis ✅ B) Nerve to vastus lateralis C) Nerve to vastus intermedius D) Nerve to rectus femoris 👉 Canal contains femoral artery, vein, saphenous nerve, nerve to vastus medialis.
Left testicular vein terminates in A) IVC B) Inferior mesenteric vein C) Splenic vein D) Left renal vein ✅ 👉 Right → IVC; Left → left renal vein.
Anal canal develops from A) Ectoderm & mesoderm B) Endoderm & ectoderm ✅ C) Mesoderm & endoderm D) Only endoderm 👉 Upper 2/3 from endoderm, lower 1/3 from ectoderm.
False statement about Peyer’s patches A) Aggregation of lymph follicles B) Help maintain bacterial flora ✅ C) Found in mesenteric border of ileum D) Part of GALT 👉 They are immune structures, not for maintaining flora.
Tarsal bone without muscular attachment A) Cuneiform B) Cuboid C) Navicular D) Talus ✅ 👉 Talus has no muscular attachment.
Muscle of deep perineal pouch A) Ischiocavernosus B) Sphincter urethrae ✅ C) Bulbospongiosus D) Superficial transverse perinei 👉 Sphincter urethrae lies in deep perineal pouch.
Gemellus inferior supplied by A) Nerve to quadratus femoris ✅ B) Nerve to obturator internus C) Superior gluteal nerve D) Inferior gluteal nerve 👉 Supplied by nerve to quadratus femoris.
Colon prone to volvulus A) Ascending B) Transverse C) Descending D) Sigmoid ✅ 👉 Sigmoid colon is most prone to volvulus.

Human Anatomy Paper II – January 2023 (Q.P. Code: 526052).

📝 Essay Questions (2 × 15 = 30 marks)

1. Sulci, gyri, functional areas on superolateral surface of cerebrum, arterial supply, applied anatomy

Sulci & gyri:

Central sulcus: Separates frontal & parietal lobes.
Lateral sulcus (Sylvian fissure): Separates frontal/parietal from temporal lobe.
Parieto‑occipital sulcus: Separates parietal & occipital lobes.
Precentral gyrus: Primary motor area.
Postcentral gyrus: Primary sensory area.
Superior, middle, inferior frontal gyri: Premotor, Broca’s area.
Superior, middle, inferior temporal gyri: Auditory cortex, Wernicke’s area.
Occipital gyri: Visual cortex.

Functional areas:

Motor (area 4), premotor (area 6), frontal eye field (area 8).
Sensory (areas 3,1,2).
Speech: Broca’s (area 44,45), Wernicke’s (area 22).
Visual (area 17), auditory (areas 41,42).

Arterial supply:

Anterior cerebral artery: Medial surface, part of superolateral.
Middle cerebral artery: Majority of superolateral surface.
Posterior cerebral artery: Occipital lobe, visual cortex.

Applied anatomy:

Stroke in MCA → contralateral hemiplegia, aphasia.
ACA occlusion → leg weakness.
PCA occlusion → visual field defects.

2. Carotid triangle – boundaries, contents, applied anatomy

Boundaries:

Anterior: Superior belly of omohyoid.
Posterior: Sternocleidomastoid.
Superior: Posterior belly of digastric, stylohyoid.

Contents:

Common carotid artery bifurcation → internal & external carotid.
Branches of external carotid (superior thyroid, lingual, facial).
Internal jugular vein.
Hypoglossal nerve, vagus nerve, ansa cervicalis.
Deep cervical lymph nodes.

Applied anatomy:

Carotid sinus (baroreceptor) & carotid body (chemoreceptor).
Site for carotid endarterectomy.
Palpation of carotid pulse.
Carotid sinus hypersensitivity → syncope.

✍️ Short Notes (10 × 5 = 50 marks)

Mediastinal surface of left lung → Impressions: heart, aortic arch, descending aorta, esophagus. Hilum: pulmonary artery, veins, bronchus.
Corpus callosum → Largest commissural fiber; parts: rostrum, genu, body, splenium; connects two cerebral hemispheres.
Pharyngeal pouches → Endodermal outpocketings; derivatives: 1st → middle ear, 2nd → tonsil, 3rd → thymus & inferior parathyroid, 4th → superior parathyroid.
Lacrimal apparatus → Lacrimal gland (secretes tears), ducts, sac, nasolacrimal duct; drains tears into nasal cavity.
Superior orbital fissure → Between greater & lesser wings of sphenoid; transmits CN III, IV, VI, ophthalmic division of CN V, ophthalmic vein.
Right atrium → Receives blood from SVC, IVC, coronary sinus; features: fossa ovalis, crista terminalis, auricle.
Histology of trachea → Lined by pseudostratified ciliated columnar epithelium with goblet cells; C‑shaped hyaline cartilage rings; smooth muscle (trachealis).
Cavernous sinus thrombosis → Infection spread from face (“danger triangle”); symptoms: ophthalmoplegia, proptosis, fever.
Left phrenic nerve → From C3–C5; descends anterior to root of lung; supplies diaphragm, pericardium, mediastinal pleura.
Muscles of mastication → Masseter, temporalis, medial & lateral pterygoids; supplied by mandibular nerve (V3); functions: elevation, depression, protrusion, retraction of mandible.

Human Anatomy Paper II – January 2023 (Q.P. Code: 526052, MCQs).

📝 MCQs with Solutions (20 × 1 = 20 marks)

Muscle inserted into anterior margin of coronoid process of mandible A) Lateral pterygoid B) Medial pterygoid C) Temporalis ✅ D) Superior constrictor 👉 Temporalis inserts into coronoid process.
Left horn of sinus venosus gives rise to A) Coronary sinus ✅ B) Oblique vein of left atrium C) Sinus venarum of right atrium D) — 👉 Left horn → coronary sinus.
Incorrect statement about Hassall’s corpuscle A) Present in thymic medulla B) Round acidophilic bodies C) Formed by concentric layers of macrophages & T‑lymphocytes ✅ D) Numerous in old age 👉 They are concentric epithelial reticular cells, not macrophages/T cells.
Narrowest space of laryngeal cavity A) Sinus of larynx B) Rima vestibuli C) Rima glottidis ✅ D) Ventricle of larynx 👉 Rima glottidis is narrowest.
Nerves crossing arch of aorta in front except A) Left phrenic nerve B) Left vagus nerve C) Left recurrent laryngeal nerve ✅ D) Superior cervical cardiac branch of left sympathetic trunk 👉 Left recurrent laryngeal passes behind.
Cricothyroid muscle develops from A) First arch B) Second arch C) Third arch D) Fourth arch ✅ 👉 Cricothyroid from 4th arch.
Spinal nucleus of trigeminal nerve receives A) Discriminative touch B) Pain & temperature ✅ C) Proprioception D) Crude touch 👉 Spinal nucleus → pain & temperature.
Depression of mandible produced by A) Temporalis B) Lateral pterygoid ✅ C) Medial pterygoid D) Masseter 👉 Lateral pterygoid opens mouth.
All are cells of epidermis except A) Merkel cells B) Monocytes ✅ C) Langerhans cells D) Melanocytes 👉 Monocytes are blood cells, not epidermal.
Anterior ethmoidal nerve is A) Branch of frontal nerve B) Branch of ophthalmic nerve C) Continuation of nasociliary nerve ✅ D) Branch of lacrimal nerve 👉 It is continuation of nasociliary.
Third ventricle communicates with fourth via A) Cerebral aqueduct of Sylvius ✅ B) Foramen of Luschka C) Foramen of Monro D) Foramen of Magendie 👉 Aqueduct connects 3rd & 4th ventricles.
Intercostobrachial nerve is A) Ventral ramus of 2nd intercostal B) Lateral cutaneous branch of 2nd intercostal ✅ C) Anterior cutaneous branch D) Medial cutaneous nerve of arm 👉 It is lateral cutaneous branch of 2nd intercostal.
Scalenus medius pierced by A) Suprascapular nerve B) Subscapular nerve C) Nerve to subclavius D) Dorsal scapular nerve ✅ 👉 Dorsal scapular pierces scalenus medius.
Internal arcuate fibers after decussation form A) Medial lemniscus ✅ B) Spinal lemniscus C) Trigeminal lemniscus D) Lateral lemniscus 👉 Internal arcuate fibers → medial lemniscus.
Lingual artery divided into three parts by A) Genioglossus B) Mylohyoid C) Styloglossus D) Hyoglossus ✅ 👉 Hyoglossus divides lingual artery.
Horizontal fissure of lung runs along A) Right 6th costal cartilage B) Right 4th costal cartilage ✅ C) Left 6th costal cartilage D) Left 4th costal cartilage 👉 Horizontal fissure at level of right 4th costal cartilage.
Nerve passing between superior & middle constrictor A) Glossopharyngeal nerve ✅ B) Internal laryngeal nerve C) Recurrent laryngeal nerve D) External laryngeal nerve 👉 Glossopharyngeal passes between.
All are tributaries of cavernous sinus except A) Superior ophthalmic vein B) Spheno‑parietal sinus C) Deep middle cerebral vein ✅ D) Superficial middle cerebral vein 👉 Deep middle cerebral vein drains elsewhere.
Bronchopulmonary lymph nodes lie in A) Hilum of lung ✅ B) Thoracic trachea C) Bifurcation of trachea D) Primary bronchus 👉 Located at hilum.
Stylohyoid ligament derived from A) Second pharyngeal arch ✅ B) Investing layer of deep cervical fascia C) First pharyngeal arch D) Pretracheal layer of deep cervical fascia 👉 Stylohyoid ligament from 2nd arch.

Physiology Paper I – January 2023 (Q.P. Code: 526053).

📝 Essay Questions (2 × 15 = 30 marks)

1. Immunity – definition, types, cell‑mediated immunity, natural killer cells

Definition: Immunity = ability of the body to resist harmful microorganisms or toxins.

Types of immunity:

Innate immunity: Non‑specific, present at birth (skin, phagocytes, complement).
Acquired immunity: Specific, develops after exposure.
- Humoral immunity: Antibody‑mediated (B lymphocytes).
- Cell‑mediated immunity: T lymphocytes.

Cell‑mediated immunity (CMI):

Mediated by T cells (helper, cytotoxic, suppressor).
Mechanism:
- Antigen presented by APCs via MHC.
- Helper T cells release cytokines → activate cytotoxic T cells.
- Cytotoxic T cells destroy infected cells, tumor cells.
Important in viral infections, graft rejection, tumor surveillance.

Natural Killer (NK) cells:

Large granular lymphocytes.
Part of innate immunity.
Kill virus‑infected and tumor cells without prior sensitization.
Use perforins and granzymes to induce apoptosis.

2. Countercurrent mechanism in kidney & Diabetes Insipidus

Countercurrent mechanism:

Operates in loop of Henle and vasa recta.
Descending limb: Permeable to water, impermeable to solutes → water leaves → fluid concentrated.
Ascending limb: Impermeable to water, actively pumps Na⁺, Cl⁻ → fluid diluted.
Creates medullary osmotic gradient.
Collecting duct: Under ADH, water reabsorbed → hypertonic urine.

Vasa recta:

Countercurrent exchange maintains gradient without washout.

Diabetes Insipidus:

Deficiency of ADH (central) or renal insensitivity (nephrogenic).
Features: Polyuria, polydipsia, dilute urine.
Treatment: Desmopressin (central type).

✍️ Short Notes (10 × 5 = 50 marks)

Na⁺/K⁺ ATPase pump → Maintains resting membrane potential; pumps 3 Na⁺ out, 2 K⁺ in; consumes ATP.
Hemolytic anemia → Premature destruction of RBCs; causes: hereditary spherocytosis, G6PD deficiency, autoimmune; features: jaundice, reticulocytosis.
Glucose reabsorption in nephron → Occurs in proximal tubule via SGLT transporters; normally complete; glycosuria when plasma glucose >180 mg/dL.
Smooth muscle structure & properties → Spindle‑shaped cells, single nucleus, non‑striated; properties: slow contraction, plasticity, involuntary control.
Body fluid compartments → Total body water ~60% body weight; ICF ~40%, ECF ~20% (plasma, interstitial fluid).
Phases of gastric juice secretion → Cephalic (vagal stimulation), gastric (food in stomach, gastrin), intestinal (chyme in intestine, inhibitory).
Dietary fibre → Non‑digestible plant material; increases stool bulk, lowers cholesterol, prevents constipation, colon cancer.
Neuroendocrine reflex → Neural stimulus triggers hormone release; e.g., suckling → oxytocin release → milk ejection.
Vitamin D in calcium homeostasis → Increases intestinal Ca²⁺ absorption, bone mineralization, renal reabsorption; deficiency → rickets, osteomalacia.
Testosterone mechanism & functions → Acts via nuclear receptors; functions: male sexual differentiation, spermatogenesis, secondary sexual characters, anabolic effects.

Physiology Paper I – January 2023 (Q.P. Code: 526053, MCQs).

📝 MCQs with Solutions (20 × 1 = 20 marks)

Regression of tissues (e.g., uterine regression after pregnancy) is a function of A) Nucleus B) Lysosomes ✅ C) Secretory vesicles D) Peroxisomes 👉 Lysosomes contain hydrolytic enzymes for autolysis.
Blood clotting is an example of A) Positive feedback ✅ B) Negative feedback C) Delayed negative feedback D) Adaptive control 👉 Clotting amplifies itself until clot is formed.
Cells attach to basal lamina via A) Zonula occludens B) Desmosomes C) Hemidesmosomes ✅ D) Claudin 👉 Hemidesmosomes anchor cells to basement membrane.
Percentage of blood volume that is plasma A) 3.5% B) 45% C) 55% ✅ D) 92% 👉 Plasma ~55%, formed elements ~45%.
Oncotic pressure exerted by plasma proteins A) 5 mmHg B) 10 mmHg C) 15 mmHg D) 25 mmHg ✅ 👉 Normal colloid osmotic pressure ~25 mmHg.
Protein transporting cell‑free hemoglobin A) Albumin B) Haptoglobin ✅ C) Hemopexin D) Transferrin 👉 Haptoglobin binds free Hb.
Muscle that cannot be tetanized A) Skeletal B) Smooth C) Cardiac ✅ D) All the above 👉 Cardiac muscle has long refractory period → no tetanus.
End plate potential characterized by A) Propagation B) All or none law C) Depolarization ✅ D) Hyperpolarization 👉 EPP is local depolarization, not propagated.
Blocks nicotinic ACh receptors postsynaptically A) Botulinum toxin B) Curare ✅ C) Neostigmine D) Tetrodotoxin 👉 Curare competitively blocks nicotinic receptors.
Slow waves in GIT initiated by A) I cells B) K cells C) Interstitial cells of Cajal ✅ D) S cells 👉 ICC are pacemakers of gut motility.
Acidification of bile occurs in A) Liver B) Hepatic duct C) Gall bladder ✅ D) Duodenum 👉 Gall bladder concentrates bile by absorbing water/ions.
Fructose transport across apical enterocyte membrane A) SGLT1 B) GLUT2 C) GLUT4 D) GLUT5 ✅ 👉 GLUT5 transports fructose.
Fraction of filtered water reabsorbed in loop of Henle A) 15% ✅ B) 25% C) 35% D) 5% 👉 Loop reabsorbs ~15% of water.
Carbonic anhydrase inhibitor diuretics act in A) Proximal tubule ✅ B) Loop of Henle C) Distal tubule D) Collecting duct 👉 Example: Acetazolamide.
Destruction of sensory nerve fibers to bladder leads to A) Atonic bladder ✅ B) Neurogenic bladder C) Hypertonic bladder D) Automatic bladder 👉 Loss of afferents → bladder fills but no reflex contraction.
Cell responsible for bone resorption A) Osteoblasts B) Osteocytes C) Osteoclasts ✅ D) Hematopoietic stem cell 👉 Osteoclasts resorb bone.
All increase GH secretion except A) Stress B) Fasting C) Exercise D) Cortisol ✅ 👉 Cortisol inhibits GH secretion.
SIADH characterized by A) Low ADH B) Decreased blood volume C) Low blood pressure D) Low serum osmolarity ✅ 👉 Excess ADH → water retention → hyponatremia, low osmolarity.
Double Bohr effect occurs in A) Lungs B) Tissues C) Placenta ✅ D) Brain 👉 Maternal & fetal Hb exchange gases in placenta.
Not true about progesterone A) Promotes breast growth B) Stimulates lobules & alveoli C) Thermogenic D) Has antiestrogenic effect on myometrial cells ✅ 👉 Progesterone relaxes myometrium but not by antiestrogenic effect.

Physiology Paper II – January 2023 (Q.P. Code: 526054).

📝 Essay Questions (2 × 15 = 30 marks)

1. Case of chest pain – diagnosis, coronary circulation, biomarkers

a) Likely diagnosis:

60‑year‑old smoker, diabetic, retrosternal pain radiating to left arm, sweating, dyspnea → Angina pectoris / Acute myocardial infarction (MI).

b) Coronary circulation peculiarities & regulation:

Peculiarities:
- Coronary arteries are end arteries (no significant anastomosis).
- Blood flow mainly during diastole (systolic compression reduces flow).
- High oxygen extraction (~70–80%).
Regulation:
- Metabolic: Adenosine, hypoxia → vasodilation.
- Neural: Sympathetic stimulation → ↑ HR & contractility → ↑ demand.
- Autoregulation: Maintains flow despite BP changes.

c) Cardiac biomarkers:

Troponin I & T: Highly specific, rise within 3–6 hrs, remain elevated 7–10 days.
CK‑MB: Rises within 3–6 hrs, peaks at 24 hrs, returns to normal in 2–3 days.
Myoglobin: Earliest marker, but non‑specific.
LDH: Rises later, less specific.

2. Respiratory centres & neural regulation of respiration

Respiratory centres:

Located in brainstem.
Medullary centres:
- Dorsal respiratory group (DRG): Inspiration, rhythm generation.
- Ventral respiratory group (VRG): Expiration, forced breathing.
Pontine centres:
- Pneumotaxic centre: Limits inspiration.
- Apneustic centre: Promotes inspiration.

Neural regulation:

Voluntary control: Cerebral cortex.
Automatic control: Medullary centres.
Chemoreceptors:
- Central (medulla): Sensitive to CO₂, H⁺.
- Peripheral (carotid & aortic bodies): Sensitive to ↓ O₂, ↑ CO₂, ↑ H⁺.
Reflexes:
- Hering–Breuer reflex (stretch receptors).
- Irritant receptors → cough reflex.
- J‑receptors → rapid shallow breathing.

✍️ Short Notes (10 × 5 = 50 marks)

Left ventricular pressure changes → Rises during isovolumetric contraction, peaks in systole (~120 mmHg), falls during relaxation, lowest in diastole.
Factors influencing venous return → Muscle pump, respiratory pump, venous tone, cardiac suction, blood volume.
CO₂ transport in blood → Dissolved (7%), carbaminohemoglobin (23%), bicarbonate (70%). Chloride shift maintains electroneutrality.
Non‑respiratory functions of lung → Filter microthrombi, metabolize vasoactive substances (ACE), immune defense, reservoir for blood.
REM vs NREM sleep →
- REM: Rapid eye movement, dreaming, muscle atonia.
- NREM: Slow wave sleep, restorative, 4 stages.
Brown‑Sequard syndrome → Hemisection of spinal cord. Features: ipsilateral motor loss & proprioception, contralateral pain & temperature loss.
Functions of hypothalamus → Autonomic regulation, endocrine control, temperature regulation, hunger, thirst, circadian rhythm, emotional behavior.
Olfactory pathway → Olfactory receptors → olfactory nerve → olfactory bulb → olfactory tract → primary olfactory cortex (piriform area).
Tests of hearing → Rinne’s test, Weber’s test, pure tone audiometry, brainstem evoked response audiometry.
Errors of refraction → Myopia (short‑sighted), hypermetropia (long‑sighted), astigmatism (irregular curvature), presbyopia (age‑related).

Physiology Paper II – January 2023 (Q.P. Code: 526054, MCQs).

📝 MCQs with Solutions (20 × 1 = 20 marks)

Heart rate in atrial flutter is about A) 95–150 B) 100–175 C) 200–350 ✅ D) >350 👉 Flutter waves ~300/min; ventricular rate ~150.
“Last ditch stand” pressure control mechanism A) Baroreceptor reflex B) Chemoreceptor reflex C) CNS ischemic response ✅ D) Atrial reflex 👉 CNS ischemic response is powerful emergency mechanism.
Frank–Starling’s law implies A) ↑ venous return → ↑ cardiac output ✅ B) ↑ vagal discharge → ↑ CO C) ↑ HR → ↑ CO D) ↑ BP → ↑ CO 👉 Stroke volume increases with end‑diastolic volume.
“Machinery murmur” heard in A) Tetralogy of Fallot B) Patent ductus arteriosus ✅ C) VSD D) ASD 👉 Continuous murmur in PDA.
Transit time across capillary A) 6–8 sec B) 10–15 sec C) 1–2 sec ✅ D) 3–4 sec 👉 Normal transit ~1 sec.
Plethysmograph uses A) Dalton’s law B) Henry’s law C) Boyle’s law ✅ D) Graham’s law 👉 Volume–pressure relation.
Physiological dead space in healthy individuals A) Double anatomical B) Equal to anatomical ✅ C) Less than anatomical D) Triple anatomical 👉 In health, they are equal.
Hering–Breuer inflation reflex activated when tidal volume is A) >500 ml B) >1000 ml ✅ C) >1500 ml D) >1200 ml 👉 Triggered at large tidal volumes.
Primary stimulus for chemosensitive neurons A) H⁺ ✅ B) CO₂ C) O₂ D) HCO₃⁻ 👉 Central chemoreceptors respond to H⁺ (from CO₂).
Respiratory exchange ratio when using fats A) 1.5 B) 0.7 ✅ C) 0.4 D) 0.8 👉 RQ for fats = 0.7.
Synapse in cerebral/cerebellar cortex located commonly in A) Axon hillock B) Dendritic spines ✅ C) Axon D) Soma 👉 Synapses occur on dendritic spines.
Jendrassik’s maneuver facilitates knee jerk by increasing discharge of A) α motor neuron B) β motor neuron C) γ motor neuron ✅ D) δ motor neuron 👉 Maneuver increases γ activity → enhances reflex.
Annulospiral endings are A) Group Ia fibres ✅ B) Group II fibres C) Dynamic γ fibres D) Static γ fibres 👉 Primary endings of muscle spindle.
Nucleus for cognitive control of motor activity A) Putamen B) Caudate ✅ C) Substantia nigra D) Subthalamus 👉 Caudate nucleus involved in cognition.
Thalamus contains inhibitory neurons in A) Midline nucleus B) Intralaminar nucleus C) Thalamic reticular nucleus ✅ D) VPL nucleus 👉 Reticular nucleus is inhibitory.
Mossy fibres in cerebellum synapse with A) Granule cells ✅ B) Purkinje cells C) Stellate cells D) Basket cells 👉 Mossy fibres → granule cells.
Normal CSF pressure lying horizontal A) 100 mm H₂O B) 90 mm H₂O C) 130 mm H₂O ✅ D) 200 mm H₂O 👉 Average ~130 mm H₂O.
Lesion in optic chiasma causes A) Binasal hemianopia B) Bitemporal hemianopia ✅ C) Contralateral homonymous hemianopia D) Ipsilateral blindness 👉 Compression of crossing fibres → bitemporal loss.
Vitamin A stored in retina in A) Ganglion cell layer B) Pigment epithelial layer ✅ C) Outer nuclear layer D) Inner nuclear layer 👉 Retinal pigment epithelium stores vitamin A.
Central fovea contains more of A) Cones ✅ B) Rods C) Both rods & cones D) Ganglion cells 👉 Fovea is cone‑rich for visual acuity.

MBBS Solved PYQ

MBBS First Professional (CBME) – Anatomy Paper I (August 2025)

Model Answers

I. Essay (10 Marks)

Question 1

a) Describe the formation, course and relations, tributaries and termination of the great saphenous vein. (1+2+3+1 Marks)

Answer

Formation

Course

Relations

Tributaries

Termination

b) Explain the anatomical basis of varicose veins. (3 Marks)

Answer

Anatomical Basis

Predisposing Factors

Clinical Features

II. Reasoning Out Short Notes (5 Marks Each)

Question 2

Answer

Question 3

Answer

Portosystemic Anastomosis

III. Short Notes (6 Marks Each)

Question 4

Answer

Boundaries

Contents

Applied Anatomy

Question 5

Answer

Question 6

Answer

Stages

Applied Anatomy

Question 7

Answer

Question 8

Answer

Features

Types

Functions

Question 9

Answer

Boundaries

Contents in Male

Contents in Female

Question 10

Answer

Cause

Causes

Clinical Features

Question 11

Answer

Lymphatic Drainage

Applied Anatomy

Question 12

Answer

Types

Factors Maintaining the Arch

Applied Anatomy

Question 13

Answer

Situation

Lobes

Blood Supply

Venous Drainage

Applied Anatomy

MBBS First Professional (CBME) – Anatomy Paper II (August 2025)

Essay & Short Notes – Model Answers

I. Essay (10 Marks)

Question 1

a) Describe the parts and relations of the internal capsule, arrangement of fibres and arterial supply of the internal capsule. (2+3+3 Marks)

Answer

Definition

Parts

Relations

Arrangement of Fibres

Arterial Supply

b) Explain the anatomical basis of the clinical features in this condition. (2 Marks)