New York State Emergency Medical Technician (EMT) Practice Exam

What is the primary function of alveoli in the lungs?

1. To produce mucus for respiration

2. To facilitate gas exchange

3. To regulate blood flow

4. To transport air to the trachea

The correct answer is: To facilitate gas exchange

The primary function of alveoli in the lungs is to facilitate gas exchange. Alveoli are tiny, balloon-like structures that provide a large surface area for the exchange of oxygen and carbon dioxide between the air in the lungs and the blood in the capillaries. Each alveolus is surrounded by a network of capillaries, allowing oxygen to diffuse into the blood while carbon dioxide diffuses from the blood into the alveoli to be exhaled. This process is essential for maintaining proper oxygen levels in the body and removing carbon dioxide, a waste product of metabolism. The other options like producing mucus, regulating blood flow, and transporting air to the trachea do not accurately represent the main role of alveoli. Mucus production typically occurs in the upper respiratory tract to trap particles; blood flow regulation is primarily handled by the heart and blood vessels; and air transport to the trachea is managed by the bronchial tubes. Therefore, the correct answer focusing on gas exchange highlights the crucial role of alveoli in overall respiratory function.