Why do blood capillaries surround alveoli?

Answer 1

The alveoli are the sites of respiration: the oxygen in them provided by the inhaled air diffuses into the blood cells that flow through the capillaries. Carbon dioxide diffuses out of the blood and into the alveoli so it can be exhaled. The capillaries provide a way for the blood to reach the alveoli. Hope this helps

Answer 2

The capillaries carry the carbon dioxide from our body cells, and require oxygen from the alveoli (to transport around the body). In other words, the alveoli are no more than 40 micrometres away from the blood, which gives a low diffusion distance for efficient gaseous transfer.

Answer 3

The alveoli are the sites of respiration: the oxygen in them provided by the inhaled air diffuses into the blood cells that flow through the capillaries. Carbon dioxide diffuses out of the blood and into the alveoli so it can be exhaled. The capillaries provide a way for the blood to reach the alveoli.

Answer 4

The alveoli are where gas exchange occurs in the lungs, the rich supply of capillaries around each of the alveoli allows this to happen effectively. Oxygen from the lungs enters the alveoli and then diffuses across the membrane into the capillaries then into the blood stream which carries the oxygen around the body. At the same time, carbon dioxide which is produced by the body diffuses from the capillaries into the alveoli to be expired out of the lungs.