Regulation of Respiration

The rhythm of normal breathing is set by the respiratory rhythm centre, located in the medulla oblongata of the hindbrain. A second centre, the pneumotaxic centre in the pons region of the brain, moderates the rhythm centre's activity to keep breathing smooth and regular rather than erratic.

Close to the rhythm centre lies a chemosensitive area that is highly sensitive to the concentration of CO2 and H+ in the blood, far more so than to oxygen - in fact, the role of O2 itself in setting the normal respiratory rhythm is comparatively minor. When CO2 and H+ levels rise, this chemosensitive area signals the rhythm centre to increase the rate and depth of breathing so that the excess CO2 (and, indirectly, H+) can be washed out of the body through exhalation. …