Question

Respiratory centres are stimulated by

• A. Oxygen
• B. Lactic acid
• C. Carbon dioxide
• D. Calcium

Answer 1

The Correct Option is C

The respiratory centers in the brain, primarily located in the medulla oblongata and pons, regulate the rate and depth of breathing by responding to chemical signals in the blood. These centers are particularly sensitive to the levels of carbon dioxide (CO₂), which is a critical factor in maintaining homeostasis in the body.

When carbon dioxide levels rise in the blood, it leads to an increase in hydrogen ions due to the formation of carbonic acid. This decrease in blood pH is detected by central and peripheral chemoreceptors, which then stimulate the respiratory centers to increase the rate and depth of respiration. This response helps to expel more CO₂ from the lungs, thereby reducing its concentration in the blood and restoring acid-base balance.

Therefore, among the given options, Carbon dioxide is the primary stimulant for respiratory centers.