What is the medical term for the air sacs in the lungs?

The correct medical term for the air sacs in the lungs is alveoli. These structures are crucial for the respiratory system as they are the sites where the exchange of oxygen and carbon dioxide occurs. Alveoli are tiny, balloon-like sacs that expand when air is inhaled and collapse when exhaled, facilitating this gas exchange process. This function is essential for maintaining proper oxygen levels in the blood and removing carbon dioxide from the body.

Other choices are related to the respiratory and circulatory systems but serve different purposes. Bronchi are the larger air passages leading from the trachea to the lungs, not the sites of gas exchange. The aorta is the main artery that carries oxygenated blood from the heart to the rest of the body, and veins are blood vessels that carry deoxygenated blood back to the heart. These terms represent different anatomical structures and functions in the body, which distinguishes them from alveoli.