Which factors primarily drive central chemoreceptors?

Central chemoreceptors, primarily located in the brainstem, play a critical role in regulating respiratory drive by responding primarily to changes in carbon dioxide (CO2) and hydrogen ion (H+) concentrations in the blood. When CO2 levels increase, it leads to an increase in hydrogen ion concentration due to the formation of carbonic acid. This process decreases the pH of the cerebrospinal fluid, which the central chemoreceptors can detect. Consequently, the activation of these receptors stimulates the respiratory centers to increase the rate and depth of ventilation, effectively aiding in the removal of CO2 from the bloodstream and restoring normal pH levels.

While oxygen levels are important for overall respiratory function, central chemoreceptors are not primarily driven by fluctuations in oxygen levels, which primarily stimulate peripheral chemoreceptors found in the carotid and aortic bodies. Thus, the interaction between CO2 and H+ levels is key for the modulation of respiration, making this option the most accurate in describing how central chemoreceptors function to maintain homeostasis in the body.