Carotid body A decrease in oxygen partial pressure, an increase in carbon dioxide partial pressure, and a decrease in arterial pH can all cause depolarization of the cell membrane, and they affect this by blocking potassium currents. This reduction in the membrane potential opens voltage-gated calcium channels, which causes a rise in intracellular calcium concentration. This causes exocytosis of vesicles containing a variety of neurotransmitters, including acetylcholine, noradrenaline, dopamine, adenosine, ATP, substance P, and met-enkephalin. These act on receptors on the afferent nerve fibres which lie in apposition to the glomus cell to cause an action potential. The feedback from the carotid
Carotid body body is sent to the cardiorespiratory centers in the medulla oblongata via the afferent branches of the glossopharyngeal nerve. The afferent fibres of the aortic body chemoreceptors are relayed by the vagus nerve. These centers, in turn, regulate breathing and blood pressure, with hypoxia causing an increase in ventilation. A paraganglioma is a tumor that may involve the carotid body and is usually benign. Rarely, a malignant neuroblastoma may originate from the carotid body. Innervated by glossopharyngeal nerve (cranial nerve IX). Carotid body The carotid body ("carotid glomus" or "glomus caroticum") is a small cluster of chemoreceptors and supporting cells