Question

If the air starts at a pressure of 1.0 atm, and you hold the volume of your lungs constant (a good approximation) and the number of molecules in your lungs stays constant as well (also a good approximation), what is the increase in pressure inside your lungs?

Answer 1

When you inhale, the pressure inside your lungs decreases, creating a negative gauge pressure and allowing air to flow in. When you exhale, the pressure inside your lungs increases, creating a positive gauge pressure and forcing air out.

Step-by-step explanation:

When you inhale, the diaphragm muscle underneath the lungs moves down, reducing the pressure inside your lungs. As a result, the pressure drops below atmospheric pressure, creating a negative gauge pressure. This negative pressure allows air to flow into the lungs. On the other hand, when you exhale, the diaphragm pushes against the lungs, increasing the pressure inside the lungs above atmospheric pressure, creating a positive gauge pressure. This increased pressure forces air out of the lungs.