The P_O2 and P_CO_2 of blood leaving the lungs is kept remarkably constant. This homeostasis is maintained by adjusting the magnitude, or volume, of respiration. Thus, it follows that changes in the magnitude of respiration are influenced by changes in P_O2 and P_CO2 in the body. Of these two gases, changes in (1)___ are the most important in regulating the magnitude of ventilation. A rise in the partial pressure of this gas triggers the body to __(2) the magnitude of ventilation. Which of the following statements correctly describes the major mechanism by which this has is monitored?
(1) P_O2 or P_CO2
(2) decrease or increase
A. Peripheral chemoreceptors in the carotid arteries monitor changes to CO_2 levels in the arterial blood.
B. Peripheral chemoreceptors in the carotid arteries monitor changes to P_CO2 levels in the arterial blood.
C. Central chemoreceptors in the medulla monitor changes to H^+ levels in the extracellular fluid
D. Central chemoreceptors in the medulla monitor changes to CO_2 levels in the extracellular fluid.