The primary stimuli that cause the respiratory center to initiate inspiration are
A) decreases in both carbon dioxide and hydrogen ion concentrations in the blood
B) a decrease in carbon dioxide and an increase in hydrogen ion concentrations in the blood
C) increases in both carbon dioxide and hydrogen ion concentrations in the blood
D) an increase in carbon dioxide and a decrease in hydrogen ion concentrations in the blood
E) a decrease in oxygen concentration and a decrease in pH in the blood

Question

Quizplus · Accepted Answer

The primary stimuli that cause the respiratory center to initiate inspiration are increases in both carbon dioxide and hydrogen ion concentrations in the blood. This is because when carbon dioxide dissolves in the blood, it forms carbonic acid, which dissociates into hydrogen ions and bicarbonate ions. The resulting increase in hydrogen ion concentration decreases blood pH, which is detected by chemoreceptors in the brainstem, leading to an increase in ventilation rate. Oxygen levels in the blood also play a role, but they are not the primary stimuli for initiating inspiration.

The Primary Stimuli That Cause the Respiratory Center to Initiate