The role of alveoli in the respiratory system is to?

The role of alveoli in the respiratory system is primarily to facilitate gas exchange. These tiny, balloon-like structures are located at the end of the respiratory tree, specifically in the lungs. Their main function is to allow for the exchange of oxygen and carbon dioxide between the air and the bloodstream.

When air reaches the alveoli, oxygen passes through their thin walls and enters the surrounding capillaries, where it binds to hemoglobin in red blood cells for transport to tissues throughout the body. At the same time, carbon dioxide, which is a waste product of cellular metabolism, diffuses from the blood into the alveoli to be exhaled. The large surface area provided by the numerous alveoli, along with their thin walls, maximizes this gas exchange process, making it highly efficient.

This function of gas exchange is vital for maintaining the body’s oxygen levels and removing carbon dioxide, which is crucial for cellular respiration and overall metabolic functions. The other choices, such as transporting oxygen, filtering air, or producing mucus, do not accurately describe the primary and specific role of alveoli in the respiratory system.