[Campbell Biology P.995] What is the primary chemical factor that most strongly influences t... | Practice Question

What is the primary chemical factor that most strongly influences the depth and rate of human breathing under normal conditions, and which brain region is primarily responsible for detecting this factor?

  • A: Oxygen concentration; Pons
  • B: Carbon dioxide concentration; Medulla oblongata
  • C: Blood pH; Cerebellum
  • D: Nitrogen concentration; Carotid arteries

Explanation

The medulla oblongata is the primary breathing control center, and it is most sensitive to changes in carbon dioxide concentration in the blood, which directly affects the pH of cerebrospinal fluid. An increase in CO2 lowers pH, stimulating increased breathing.