# How are the alveoli designed to maximise

Question.
How are the alveoli designed to maximise the exchange of gases?

solution:
Alveoli are small pouches or sacs. Large number of alveoli occur inside each lung.

The whole surface of an alveolus functions as respiratory surface.

Due to large number of alveoli in each lung, a very large area of respiratory surface becomes available (about $80 \mathrm{~m}^{2}$ ) for exchange of gases. The walls of alveoli are very thin and they are surrounded by blood capillaries.