Question

A 10 percent increase in the level of carbon dioxide in the blood will select one:

a. decrease pulmonary ventilation.
b. decrease the alveolar ventilation rate.
c. decrease the vital capacity.
d. increase the rate of breathing.
e. decrease the rate of breathing.

Answer 1

The correct answer is d. increase the rate of breathing.

Peripheral chemoreceptors (the carotid and aortic bodies) can sense hypercapnia (high CO2) and then they send a signal to the breathing centre. Breathing centre is in medulla oblongata which regulates breathing movements. When CO2 reaches a certain level, a signal is sent to trigger an inhalation and the rate of breathing is increased.