Which of the following is a factor on which expiration depends?
A)contraction of expiratory muscles
B)increase in lung volume
C)recoil of elastic tissue in the lungs
D)decrease in intrapulmonary pressure

Question

Quizplus · Accepted Answer

Expiration depends on the recoil of elastic tissue in the lungs. During inspiration, the diaphragm contracts and the intercostal muscles expand the ribcage, which increases the volume of the thoracic cavity. This decrease in intrathoracic pressure causes air to flow into the lungs. During expiration, the diaphragm and intercostal muscles relax, which decreases the volume of the thoracic cavity. The elastic recoil of the lungs causes them to return to their resting state, which increases the pressure in the lungs and forces air out. Therefore, the recoil of elastic tissue in the lungs is a major factor on which expiration depends.

Which of the Following Is a Factor on Which Expiration