What is the primary role of the alveoli in the respiratory system?

The primary role of the alveoli in the respiratory system is to facilitate the exchange of oxygen and carbon dioxide. Alveoli are tiny air sacs located at the ends of the bronchioles in the lungs, where the exchange of gases occurs.

When air is inhaled into the lungs, it reaches the alveoli, where oxygen from the air passes through their thin walls into the surrounding capillaries, entering the bloodstream. At the same time, carbon dioxide from the blood moves into the alveoli to be exhaled. This efficient gas exchange is critical for maintaining the body’s oxygen levels and removing carbon dioxide, a waste product of metabolism.

This function is vital for cellular respiration, the process by which cells generate energy. Without the proper functioning of alveoli, the body's ability to obtain oxygen and expel carbon dioxide would be severely compromised, leading to respiratory failure and other serious health issues.