The exhalation of air from human lungs is driven by ________.
A) a decrease in the volume of the thoracic cavity with an associated increase in thoracic pressure
B) a decrease in the residual volume of the lungs
C) the contraction of the diaphragm
D) the closure of the epiglottis
E) the expansion of the rib cage

Question

Quizplus · Accepted Answer

The exhalation of air from human lungs is driven by the decrease in the volume of the thoracic cavity with an associated increase in thoracic pressure. This reduces the pressure inside the lungs, causing air to move out. The muscles involved in this process include the intercostal muscles and the diaphragm. However, the diaphragm is primarily involved in inhalation, whereas exhalation is mainly due to the relaxation of these muscles and the elastic recoil of the lungs. The closure of the epiglottis is involved in preventing food or liquid from entering the trachea during swallowing, and the expansion of the rib cage is involved in inhalation. Therefore, the best choice is A.

The Exhalation of Air from Human Lungs Is Driven by ________