What are the tiny air sacs in the lungs called that facilitate gas exchange?

• A. Bronchi
• B. Alveoli
• C. Larynx
• D. Diaphragm

Answer: (B)

The tiny air sacs in the lungs that facilitate gas exchange are called alveoli. These structures are crucial for respiration as they provide a large surface area for the exchange of oxygen and carbon dioxide between the air we breathe and the blood in the capillaries that surround them.

The alveoli are designed to maximize efficiency in gas exchange; they are lined with a thin layer of cells, which allows for easy diffusion of gases. Oxygen from the inhaled air passes through the alveolar walls into the bloodstream, where it binds to red blood cells. Conversely, carbon dioxide, which is a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled. This process is vital for maintaining the body’s oxygen levels and removing carbon dioxide, therefore supporting cellular respiration and overall metabolic function.