Milady Anatomy Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

The alveoli play a crucial role in the respiratory system by facilitating gas exchange. These tiny, balloon-like structures are located at the end of the bronchioles within the lungs and are surrounded by a network of capillaries. As air is inhaled into the lungs, the oxygen it contains diffuses across the thin walls of the alveoli into the bloodstream. At the same time, carbon dioxide, which is a waste product of metabolism, moves from the blood into the alveoli to be exhaled. This exchange of oxygen and carbon dioxide is essential for maintaining the body's overall gas balance and supporting cellular respiration.

While filtering air, producing mucus, and regulating blood flow are important functions in the respiratory and circulatory systems, they do not directly pertain to the primary function of the alveoli. The main purpose of these structures is specifically to enable the efficient transfer of gases, making their role in gas exchange critical for respiratory health and overall physiological function.