Robert S Fitzgerald
Departments of Environmental Health and Engineering, The Johns Hopkins University Medical Institutions, Baltimore, MD-21205,
Tanzania
Research Article
The Carotid Body: Terrestrial Mammals' Most Important Peripheral
Neuroreceptor?
Author(s): Robert S FitzgeraldRobert S Fitzgerald
The carotid body (CB) is a tiny structure, bilaterally located at the bifurcation of the common carotid artery into its internal and external branches, is innervated by a branch of cranial nerve IX, and sends its neural output to the nucleus tractus solitarius in the medulla. Arterial flow through the CB is the highest of any organ ever measured. The CB is the unique sensor of decreases in PaO2, but is also stimulated by low glucose as well as increases in PaCO2, [H+]a, temperature, and osmolarity. Hypoxia-generated increases in neural activity result from K+ channels in the CB's neurotransmitter-containing glomus (Type I) cells being blocked; this depolarizes the cells allowing calcium to enter, which promotes the movement of the glomus cells' transmitter-containing vesicles to exocytose ACh and ATP into the gap between cell and an abutting afferent fiber, where these agents bind to .. View More»
