Question

Describe the mechanism of exchange of gases in the alveolus of the lung.

Answer 1

The exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.

Answer 2

Answer:

Bronchioles in the lungs have tiny air sacs at their ends called alveoli. Each lung contains millions of alveoli. The air from trachea, through the bronchi and  bronchioles, finally enters the alveoli. The oxygen of the air diffuses out from the walls of alveoli into blood capillaries. The oxygen is carried to all the cells in the body. Then carbon dioxide is produced by the breakdown of food. This $CO^{2}$ now enters the blood. $CO^{2}$ in the blood is carried to the alveoli. From the lungs the $CO^{2}$ is removed by exhalation.

In this way exchange of gases takes place in alveoli.