What is the typical structure of the alveoli?

The typical structure of the alveoli consists of tiny, sac-like structures that are crucial for the respiratory system's function. Alveoli are the endpoints of the respiratory tract and are where gas exchange occurs. Their sac-like design provides a large surface area relative to their volume, which facilitates efficient gas exchange between the air in the alveoli and the blood in the surrounding capillaries.

This structural feature allows for the maximization of oxygen intake and carbon dioxide removal, as the thin walls (made up of a single layer of epithelial cells) enable gases to pass through easily. Therefore, the characteristic sac-like shape of the alveoli is essential for their primary role in respiration—ensuring that the body gets the oxygen it needs while expelling carbon dioxide effectively.