Question

What are alveoli ? where are they found ?how they make up the lungs ? What are their functions?

Answer 1

Alveoli are small air sacs in the lungs, as small as a grain of sand. There are billions of these in the lungs, and the purpose of these alveoli are to supply de-oxygenated blood with a supply of oxygen through gas exchange. They are well-equipped to do this, as well. The first reason is because the cappillaries that the alveoli are supplying with oxygen are spread all over the outside of them, meaning there is more surface area to perform gaseous exchange on. The second reason is because the alveoli walls are only one cell thick, meaning the oxygen only has two cells to go through, the alveoli wall, and the capillary wall.
They are tiny pockets in the lungs at the end of the bronchioles, where oxygen diffuses into the blood and carbon dioxide diffuses out of the blood. . The alveoli increase the overall internal surface area of the lungs, so that more oxygen and carbon dioxide can diffuse in and out. these are the tiny air sacs in the lungs