MICROANATOMY

Detailed explanation-1: -Alveoli are wrapped in tiny blood vessels called capillaries. The air you breathe in fills these air sacs with oxygen-rich air. This is where the exchange of gases occurs.

Detailed explanation-2: -Gas 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.

Detailed explanation-3: -Oxygen passes quickly through this air-blood barrier into the blood in the capillaries. Similarly, carbon dioxide passes from the blood into the alveoli and is then exhaled.

Detailed explanation-4: -Gas exchange takes place between blood and alveoli in the lungs, and then between blood and tissue cells all around the body through simple diffusion. Gasses cross the membranes at the alveolar-capillary membrane in the lungs, where oxygen enters and carbon dioxide exits the bloodstream.