Branch of glossopharyngeal nerve to carotid sinus help maintain a more consistent blood pressure) and from chemoreceptors in the carotid body (mainly monitoring blood gas PaO2 and PaCO2 levels). Hering's nerve responds to both increases and decreases in blood pressure while the baroreceptors in the aortic arch respond only to increases in blood pressure . Branch of glossopharyngeal nerve to carotid sinus The branch of glossopharyngeal nerve to the carotid sinus (Hering's nerve) is a small nerve in the neck, that innervates the carotid sinus and the carotid body. It is a branch of the glossopharyngeal nerve that runs downwards, anterior to the internal carotid artery. It
Carotid body acid-base transporters (e.g. Na-H) which raise intracellular pH, and activates transporters (e.g. Cl-HCO) which decrease it. Changes in proton concentration caused by acidosis (or the opposite from alkalosis) inside the cell stimulates the same pathways involved in P sensing. Another mechanism is through oxygen sensitive potassium channels. A drop in dissolved oxygen lead to closing of these channels which results in depolarization. This leads to release of the neurotransmitter dopamine in the glossopharyngeal and vagus afferente to the vasomotor area. The type I (glomus) cells in the carotid (and aortic bodies) are derived from neuroectoderm and are thus electrically excitable.