What role do alveoli play in the respiratory system?

The role of alveoli in the respiratory system is primarily centered around gas exchange. Alveoli are tiny, balloon-shaped structures located in the lungs where the exchange of oxygen and carbon dioxide occurs. These small air sacs are richly surrounded by a network of capillaries, allowing for the efficient transfer of gases due to their large surface area and thin walls.

When oxygen enters the alveoli during inhalation, it diffuses across the alveolar wall into the bloodstream, where it binds to hemoglobin in red blood cells. Simultaneously, carbon dioxide, which is a waste product produced by the body's metabolism, diffuses from the blood into the alveoli to be expelled during exhalation. This critical function of gas exchange is essential for respiration and maintaining homeostasis within the body, ensuring that oxygen is available for cellular processes and that carbon dioxide is effectively removed.

While other functions such as producing mucus, filtering air, and controlling pH are important in the respiratory system, they are not the primary roles of alveoli. Mucus production mainly occurs in the mucous membranes of the airway, air filtering is primarily done by structures like the nose and trachea, and the body regulates pH through various systems, including the respiratory system's