Regulation of Respiration

Breathing is not fixed at one steady pace — the body constantly adjusts it to match what the tissues need at the moment, whether at rest or during exertion. This fine control is handled by the nervous system rather than by conscious effort.

The respiratory rhythm centre

The main control lies in the medulla region of the brain, where a specialised centre called the respiratory rhythm centre sets and maintains the basic rhythm of breathing.

The pneumotaxic centre

A second centre, the pneumotaxic centre, is located in the pons region of the brain. It can moderate the activity of the respiratory rhythm centre: signals from it can shorten the duration of inspiration, and by doing so it alters the overall respiratory rate.

Sensing carbon dioxide and acidity

Right next to the rhythm centre is a chemosensitive area that is highly sensitive to carbon dioxide and hydrogen ions. When the levels of these substances rise, this area is activated and signals the rhythm centre to adjust breathing so that the excess carbon dioxide and hydrogen ions can be eliminated. …