Which receptors in the respiratory system are primarily stimulated by increased CO2 levels?

Which receptors in the respiratory system are primarily stimulated by increased CO2 levels?

• A. Baroreceptors
• B. Central chemoreceptors
• C. Peripheral chemoreceptors
• D. Olfactory receptors

Answer: (B)

The correct answer is central chemoreceptors, which are primarily stimulated by increased levels of carbon dioxide (CO2) in the blood. These receptors are located in a part of the brain called the medulla oblongata. When CO2 levels rise, they lead to a decrease in pH of the cerebrospinal fluid, creating an acidic environment. This change is detected by the central chemoreceptors, which respond by signaling the respiratory centers to increase the rate and depth of breathing. This response helps to expel CO2 from the body and restore normal acid-base balance.

Understanding the role of central chemoreceptors is crucial for grasping how the body regulates breathing in response to changes in metabolic demands. In contrast, while peripheral chemoreceptors are involved in detecting changes in oxygen levels and blood pH, they play a secondary role compared to the central chemoreceptors in response to CO2 fluctuations. Baroreceptors primarily monitor blood pressure, and olfactory receptors are responsible for the sense of smell, which is unrelated to the regulation of respiration in relation to CO2 levels.