What is a key feature of alveoli in the lungs?

The key feature of alveoli in the lungs is that they are tiny air sacs. This structure is essential for the primary function of alveoli, which is to facilitate gas exchange. Each alveolus is surrounded by a network of capillaries that allow oxygen to diffuse into the blood and carbon dioxide to diffuse out. Their small size maximizes the surface area available for gas exchange, which is vital for efficient respiratory function. Additionally, the thin walls of the alveoli enable rapid diffusion of gases, making them highly effective in the process of respiration. This unique anatomical configuration ensures that the lungs can effectively oxygenate the blood while expelling carbon dioxide, a critical aspect of maintaining homeostasis in the body.