Respiration is controlled by a respiratory center in the:

• A. Cerebellum
• B. Medulla
• C. Hypothalamus
• D. Pons

Answer: (B)

Breathing is controlled by automatic brainstem centers that set the rhythm and depth of respiration. The medulla oblongata houses the main respiratory rhythm generators—the dorsal respiratory group drives inhalation and the ventral respiratory group contributes to expiration and more forceful breathing when needed. These medullary centers respond to chemical signals, especially CO2 levels reflected as hydrogen ion concentration, via central chemoreceptors and input from peripheral chemoreceptors, adjusting rate and depth accordingly. The pons helps smooth and coordinate breathing, modulating transitions between inhalation and exhalation. The cerebellum coordinates movement but doesn’t establish the breathing rhythm, and the hypothalamus can influence breathing in response to emotions or temperature but isn’t the primary controller. Hence, the medulla is the key site for respiratory control.