To maintain life, we absorb oxygen from the air. And we export carbon dioxide from the body.
Human respiratory organs include nose, organs, bronchi, lungs.
Each bronchus in the lung continues to diverge and taper. The end of this thin branch is connected to the alveoli. The alveoli is a very thin air bag.
The surface of the alveoli is surrounded by capillaries. In alveolar gas exchange occurs between air and blood. Since the lungs consist of many alveoli, the surface area is very wide. Therefore, the exchange of gas between the air and the blood can occur quickly and easily.