Question

How are alveoli designed to maximize the exchange of gases?

• A. By increasing the surface area of trachea
• B. By decreasing the surface area of the lungs
• C. By increasing the surface area of the lungs for gaseous exchange
• D. None of the above

Answer 1

The correct option is C By increasing the surface area of the lungs for gaseous exchange

Alveoli are small pouches or sacs. Large number of alveoli occur inside each lung. The whole surface area of an alveolus functions as a respiratory surface. Due to large number of alveoli in each lung, a very large area of respiratory surface becomes available (about $80m^2$) for exchange of gases. Thus, alveoli are designed to maximize the exchange of gases.

Therefore, the correct answer is option C.