Which of the Following Events Occurs Last

Question

Which of the following events occurs last?
A) Contraction of the diaphragm and the intercostals
B) Movement of air into the lungs
C) Firing of the inspiratory neurons in the medulla
D) Firing of the phrenic and intercostal nerves

Accepted Answer

Movement of air into the lungs occurs after the contraction of the diaphragm and intercostals (A) and firing of the phrenic and intercostal nerves (D), which are necessary for the expansion of the thoracic cavity. However, these events are all triggered by the firing of inspiratory neurons in the medulla (C), which occurs first.