Question

Explain how the exchange of gases takes place in the alveoli?

Answer 1

Gaseous exchanges in Respiratory system

Alveoli:

1. Exchange of respiratory gases, oxygen and carbon-dioxide, takes place in the alveoli.
2. The alveoli of the lungs have a special structure for efficient exchange of respiratory gases.
3. They have thin and moist walls, which enable gaseous diffusion.

Diffusion of oxygen:

1. Oxygen which is inhaled from the atmosphere diffuses through the walls of the alveoli and reaches the bloodstream and into the red blood cells during gaseous exchange.
2. It binds to the haemoglobin present in the red blood cells and is transported to all the tissues of the body.

Diffusion of carbon dioxide:

• Carbon dioxide produced by the metabolism reaches the lung via the bloodstream at the same time.
• It then diffuses across the capillary and alveolar walls and is carried by the respiratory tract and exhaled out into the air.