Respiratory System Physiology (Degree Level)
The respiratory system is responsible for gas exchange — supplying oxygen to the blood and removing carbon dioxide. It consists of the airways, lungs, alveoli, and muscles of respiration.
Key Processes:
1. Ventilation
- Movement of air in and out of lungs.
- Inhalation: Diaphragm contracts (moves down), intercostal muscles expand rib cage → lung volume increases → pressure inside lungs drops → air flows in.
- Exhalation: Diaphragm relaxes (moves up), rib cage compresses → lung volume decreases → pressure inside lungs rises → air flows out.
2. Gas Exchange
- Occurs in alveoli, tiny air sacs surrounded by capillaries.
- Oxygen diffuses from alveoli → blood.
- Carbon dioxide diffuses from blood → alveoli.
3. Transport of gases
- Oxygen binds to hemoglobin in red blood cells.
- Carbon dioxide transported dissolved, bound to proteins, or as bicarbonate.
4. Regulation of Breathing
- Controlled by respiratory centers in brainstem (medulla & pons).
- Sensors monitor blood CO₂, O₂, and pH to adjust breathing rate/depth.
Interactive Animation Model
This animation demonstrates how ventilation works — the diaphragm and lung volume changing with inhalation and exhalation.
How to use:
- Press the Start Animation button to watch the breathing cycle with descriptions.
Respiratory System Breathing Cycle
Press Start to see how breathing works!