What role do alveoli play in the respiratory system?

The alveoli play a critical role in the respiratory system as the primary sites for gas exchange. These small, balloon-like structures are located at the ends of the bronchioles in the lungs and are essential for the process of respiration. When air is inhaled, it travels through the respiratory tract and reaches the alveoli, where oxygen from the inhaled air diffuses across the thin walls of the alveoli into the bloodstream. Simultaneously, carbon dioxide, which is a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled. This efficient exchange of gases is vital for maintaining the body’s oxygen levels and removing carbon dioxide, thus supporting cellular respiration and overall metabolic function.