Question

How does exchange of respiratory gases take place in the alveoli or lungs?

Answer 1

Exchange of respiratory gases, oxygen and carbon dioxide take place in the alveoli of the lungs. Oxygen which is inhaled from the atmosphere diffuses through the walls of the alveoli and reaches to the adjacent capillaries into the red blood cells. It binds to haemoglobin present in red blood cells and is transported to all the tissues of the body. Carbon dioxide produced by the metabolism reaches the lung via the blood. It then diffuses across the capillary and alveolar walls into the air to be exhaled out from the body. The alveoli of the lungs have a specialized structure for efficient exchange of respiratory gases. It has extremely thin walls. It has large surface area to volume. It is surrounded by many blood capillaries.