Alveoli are a thin-walled, tiny balloon-shaped, tiny sacs like structure present within our lungs. They are a moist membrane, which functions by supporting the easy movement of oxygen and carbon dioxide between the lungs and bloodstream.
Alveoli are the smallest passageway in the respiratory system and are richly supplied with a network of blood vessels. There are many alveoli and are the only cell that plays a significant role in gas exchange.
The alveoli are called as the structural and functional unit of lungs. They are the final branches of the human respiratory system, which are located at the ends of the air passageways in the lungs. Thus, it has a maximum surface for exchange of gases.
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