Which do central chemoreceptors respond to?

Which do central chemoreceptors respond to?

• A. Oxygen tension in arterial blood
• B. Carbon dioxide partial pressure in arterial blood
• C. Hydrogen ions in cerebrospinal fluid
• D. Bicarbonate in cerebrospinal fluid

Answer: (C)

Central chemoreceptors monitor the hydrogen ion concentration (pH) of the cerebrospinal fluid. When arterial CO2 rises, CO2 diffuses into the CSF and forms carbonic acid, which dissociates to H+ and bicarbonate, increasing H+ and lowering CSF pH. That change in CSF pH stimulates these receptors, driving increased ventilation to blow off CO2 and raise pH. Oxygen levels in arterial blood are detected mainly by peripheral chemoreceptors, not central ones. Bicarbonate in CSF isn’t the primary cue for these receptors; it’s the hydrogen ion concentration (CSF pH) that matters.

Central chemoreceptors monitor the hydrogen ion concentration (pH) of the cerebrospinal fluid. When arterial CO2 rises, CO2 diffuses into the CSF and forms carbonic acid, which dissociates to H+ and bicarbonate, increasing H+ and lowering CSF pH. That change in CSF pH stimulates these receptors, driving increased ventilation to blow off CO2 and raise pH. Oxygen levels in arterial blood are detected mainly by peripheral chemoreceptors, not central ones. Bicarbonate in CSF isn’t the primary cue for these receptors; it’s the hydrogen ion concentration (CSF pH) that matters.