High resolution

Module 10: Figure breathing control

Location of the gas sensing systems that control breathing.

The peripheral chemoreceptors located in the carotid and aortic bodies respond to small decreases in the level of O2 by exciting sensory neurons that relay information to the respiratory centre in the medulla oblongata via the nucleus tractus solitarii (NTS). The respiratory centre contains the central chemoreceptors that are particularly sensitive to increases in either CO2/H+ or ATP levels, which act to accelerate the neuronal respiratory circuits that controls breathing. This respiratory centre communicates with the diaphragm and intercostal muscles via the phrenic nerve. The structure and function of the carotid body is illustrated in Module 10: Figure carotid body chemoreception, whereas the respiratory centre in the pre-Bötzinger region is illustrated in Module 10: Figure respiratory pacemaker circuit.