Contraction of the Diaphragm and the External Intercostal Muscles

Question

Contraction of the diaphragm and the external intercostal muscles
A) stimulates the phrenic and intercostal nerves.
B) decreases thoracic volume.
C) causes air to move out of the lungs.
D) is responsible for inhalation.

Accepted Answer

Contraction of the diaphragm and external intercostal muscles causes an increase in thoracic volume and a decrease in intrapulmonary pressure, which allows air to move into the lungs. Therefore, this contraction is responsible for inhalation, not exhalation.