Exhalation Begins When

Question

Exhalation begins when
A) inspiratory muscles relax.
B) the diaphragm contracts.
C) blood circulation is the lowest.
D) inspiratory muscles relax and the diaphragm contracts.
E) All of these choices.

Accepted Answer

Exhalation begins when the inspiratory muscles relax, allowing the diaphragm to move upwards and the rib cage to move downwards, decreasing the volume of the thoracic cavity and forcing air out of the lungs.