Question

Chemosensitive areas are situated close to respiratory rhythm centres and are found in CNS. These are mainly sensitive to ------------------.

• A. CO₂ but not H⁺ changes
• B. ${\mathrm{}}^{}$H⁺ but not CO₂ changes
• C. both CO₂ and H⁺ changes
• D. $\mathrm{}$CO₂ and O₂ but not H⁺ changes

Answer 1

Answer: (C)

A specialised centre present in the medulla region of the brain, called respiratory rhythm centre, is primarily responsible for this regulation. Another centre present in the pons region of the brain, called pneumotaxic centre, can moderate the functions of the respiratory rhythm centre. The neural signal from this centre can reduce the duration of inspiration and thereby, alter the respiratory rate. A chemosensitive area is situated adjacent to the rhythm centre which is highly sensitive to ${\mathrm{C}\mathrm{O}}_2$ and hydrogen ions. Increase in these substances can activate this centre, which in turn can signal the rhythm centre to make necessary adjustments in the respiratory process, by which these substances can be eliminated.