Active expiration is produced by contraction of
A) abdominal muscles only.
B) diaphragm only.
C) internal intercostals only.
D) external intercostals only.
E) abdominal muscles and internal intercostals.

Question

Quizplus · Accepted Answer

Active expiration is caused by the contraction of the abdominal muscles and the internal intercostal muscles. The abdominal muscles help increase the pressure in the abdominal cavity, pushing the diaphragm up and forcing air out of the lungs, while the internal intercostal muscles help pull the ribs downward, also helping to force air out. The diaphragm and external intercostal muscles are primarily involved in inhalation, not expiration.

Active Expiration Is Produced by Contraction of