What regulates ventilation?

What regulates ventilation?

• A. Signals from the cerebral cortex that are unrelated to blood gases.
• B. Bone marrow production of red blood cells.
• C. Homeostasis of blood gases and pH through rate and depth of breathing.
• D. Digestive tract motility controlling breathing.

Answer: (C)

Ventilation is regulated by chemical feedback that keeps blood gases and pH within tight limits. The brainstem’s respiratory centers adjust how fast and how deeply you breathe in response to signals from chemoreceptors. Central chemoreceptors, located in the medulla, sense the hydrogen ion concentration in the CSF, which reflects CO2 levels in the blood; when CO2 rises, the resulting acidity of CSF drives an increase in ventilation to blow off CO2 and restore pH. Peripheral chemoreceptors in the carotid and aortic bodies respond to low arterial O2, high CO2, or low pH, providing an additional drive to breathe, especially when oxygen is scarce. The overall effect is homeostatic control of ventilation via rate and depth of breathing. Other signals, like those from the cerebral cortex that are unrelated to blood gases, don’t sustain breathing regulation in response to chemical changes, and processes such as bone marrow production of red blood cells or digestive tract motility don’t directly regulate ventilation on a moment-to-moment basis.

Ventilation is regulated by chemical feedback that keeps blood gases and pH within tight limits. The brainstem’s respiratory centers adjust how fast and how deeply you breathe in response to signals from chemoreceptors. Central chemoreceptors, located in the medulla, sense the hydrogen ion concentration in the CSF, which reflects CO2 levels in the blood; when CO2 rises, the resulting acidity of CSF drives an increase in ventilation to blow off CO2 and restore pH. Peripheral chemoreceptors in the carotid and aortic bodies respond to low arterial O2, high CO2, or low pH, providing an additional drive to breathe, especially when oxygen is scarce. The overall effect is homeostatic control of ventilation via rate and depth of breathing.

Other signals, like those from the cerebral cortex that are unrelated to blood gases, don’t sustain breathing regulation in response to chemical changes, and processes such as bone marrow production of red blood cells or digestive tract motility don’t directly regulate ventilation on a moment-to-moment basis.