Question

Explain why, when air is taken in and let out during breathing, the lungs always contain a residual volume of air.

Answer 1

Residual volume:

1. Residual volume is the amount of gas remaining in the lungs at the end of a maximal exhalation.
   
2. If the lungs removed all the air from itself while exhaling the air out of the system, it would collapse because the entire muscle would come together while contracting.
3. Residual volume is important because it prevents the lungs from collapsing.
   
4. Even after we have expelled as much air as possible (expiratory reserve volume) gaseous exchange is still occurring by residual volume in the lungs.
   
5. It also prevents the inner surfaces of the lungs from sticking together.