Which brain structure regulates ventilation?

• A. Pons
• B. Cerebellum
• C. Medulla
• D. Cerebral cortex

Answer: (C)

Ventilation is controlled primarily by brainstem respiratory centers, with the medulla oblongata providing the essential regulatory drive that sets the breathing rhythm. The medulla houses the groups that generate and coordinate breathing—driving inhalation and coordinating exhalation—and it integrates input from chemoreceptors that monitor carbon dioxide and pH, as well as oxygen levels, to adjust rate and depth automatically. The pons modulates this rhythm, refining the pattern, but the medulla is the main regulator of automatic breathing. The cerebellum is involved in coordinating movement and balance, not breathing. The cerebral cortex can influence breathing voluntarily, such as when you hold your breath or speak, but steady, automatic ventilation under resting conditions comes from the medullary centers.