What is the role of chemoreceptors in respiratory regulation?

• A. To exchange oxygen and carbon dioxide
• B. To detect changes in blood gases and pH
• C. To regulate heart rate
• D. To control body temperature

Answer: (B)

Chemoreceptors play a crucial role in respiratory regulation by detecting changes in the levels of blood gases—specifically oxygen (O2) and carbon dioxide (CO2)—as well as monitoring pH levels. These specialized sensory receptors are positioned in key areas, such as the carotid bodies and the medulla oblongata, where they are sensitive to alterations in arterial blood chemistry.

When CO2 levels rise, it leads to a decrease in pH (increased acidity), which signals the chemoreceptors to stimulate the respiratory center in the brain. This activation prompts an increase in the rate and depth of breathing, facilitating the removal of CO2 from the body while simultaneously enhancing oxygen intake. Conversely, if blood O2 levels drop, chemoreceptors also signal for adjustments in breathing patterns to ensure that adequate oxygen is supplied to meet the body's demands.

The other choices do not align with the primary functions of chemoreceptors. For instance, while gas exchange is an essential respiratory function, it occurs in the alveoli and lungs rather than via chemoreceptors. Similarly, heart rate regulation and body temperature control are managed by different physiological mechanisms and systems within the body, such as the cardiovascular and thermoregulatory systems, respectively.