Glomus cells are the cell type mainly located in the carotid bodies and aortic bodies. Glomus type I cells are peripheral chemoreceptors which sense the oxygen, carbon dioxide and pH levels of the blood. When there is a decrease in the blood's pH, a decrease in oxygen (pO2), or an increase in carbon dioxide (pCO2), the carotid bodies and the aortic bodies signal the dorsal respiratory group in the medulla oblongata to increase the volume and rate of breathing. The glomus cells have a high metabolic rate and good blood perfusion and thus are sensitive to changes in arterial blood gas tension. Glomus type II cells are sustentacular cells having a similar supportive function to glial cells.
Development of the nervous system. The glomus type I cells of the carotid body are derived from the neural crest and can be seen in green.
Glomus type I cells are embryonically derived from the neural crest. In the carotid body the respiratory chemoreceptors need a period of time postnatally in order to reach functional maturity. This maturation period is known as resetting. At birth the chemorecptors express a low sensitivity for lack of oxygen but this increases over the first few days or weeks of life. The mechanisms underlying the postnatal maturity of chemotransduction are obscure.
Clusters of glomus cells, of which the carotid bodies and aortic bodies are the most important, are called non-chromaffin or parasympathetic paraganglia. They are also present along the vagus nerve, in the inner ears, in the lungs, and at other sites. Neoplasms of glomus cells are known as paraganglioma, among other names, they are generally non-malignant.
^Lahiri S, Semenza G, Prabhakar NR, eds. (2003). Oxygen sensing : responses and adaptation to Hypoxia. New York: Dekker. pp. 200, 232. ISBN978-0824709600.
^ abPearse AG, Polak JM, Rost FW, Fontaine J, Le Lièvre C, Le Douarin N (1973). "Demonstration of the neural crest origin of type I (APUD) cells in the avian carotid body, using a cytochemical marker system". Histochemie. 34 (3): 191-203. doi:10.1007/bf00303435. PMID4693636.
^ abCarroll, JL; Kim, I (15 November 2005). "Postnatal development of carotid body glomus cell O2 sensitivity". Respiratory Physiology & Neurobiology. 149 (1-3): 201-15. doi:10.1016/j.resp.2005.04.009. PMID15886071.