Question

Central chemoreceptors that monitor composition of cerebrospinal fluid will trigger an increase in ventilation ________.

a) When CO2 levels in the blood rise
b) When oxygen levels in the blood decrease
c) Irrespective of blood composition
d) When blood pH becomes more alkaline

Answer 1

Central chemoreceptors will trigger an increase in ventilation when CO2 levels in the blood rise, leading to increased hydrogen ions and a decreased pH in the cerebrospinal fluid.

Step-by-step explanation:

Central chemoreceptors monitor the composition of cerebrospinal fluid and will trigger an increase in ventilation when CO2 levels in the blood rise. As CO2 levels increase, it diffuses across the blood-brain barrier into the extracellular fluid. The resultant rise in hydrogen ion concentration leads to a decrease in pH, which central chemoreceptors detect and respond to by signaling the respiratory centers to increase the rate and depth of ventilation. This process expels more carbon dioxide, which then helps to normalize blood levels of CO2 and hydrogen ions, thereby adjusting the pH towards normal.