What is alveoli? What are its …

Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in balloon-like structures which are called alveoli. The alveoli provide a surface where the exchange of gases can take place. The walls of the alveoli contain an extensive network of blood-vessels. When we breathe in, the ribs are lift up and the diaphragm flattens which increases the size of the chest cavity. Because of this, air is sucked into the lungs and fills the expanded alveoli.

Alveoli are the tiny air sacs (only 1 cell thick) in the lungs at the end of the smallest airways, where the exchange of oxygen and carbon dioxide takes place. The average human has nearly 300 million alveoli to absorb oxygen from the air.

Function of alveoli

The function of the alveoli is to get oxygen into the blood stream for transport to the tissues, and to remove carbon dioxide from the blood stream.