Internal carotid artery Internal carotid artery The internal carotid artery is a major paired artery, one on each side of the head and neck, in human anatomy. They arise from the common carotid arteries where these bifurcate into the internal and external carotid arteries at cervical vertebral level 3 or 4; the internal carotid artery supplies the brain, while the external carotid nourishes other portions of the head, such as face, scalp, skull, and meninges. Terminologia Anatomica in 1998 subdivided the artery into four parts: "cervical", "petrous", "cavernous", and "cerebral". However, in clinical settings, the classification system of the internal carotid artery usually
Carotid body may involve mitochondrial oxygen sensors and the haem-containing cytochromes that undergo reversible one-electron reduction during oxidative-phosphorylation. Haem reversibly binds O with an affinity similar to that of the carotid body, suggesting that haem containing proteins may have a role in O, potentially this could be one of the complexes involved in oxidative-phosphorylation. This leads to increases in reactive oxygen species and rises in intracellular Ca. However, whether hypoxia leads to an increase or decrease in reactive oxygen species is unknown. The role of reactive oxygen species in hypoxia sensing is also under question. The oxygen dependent enzyme haem-oxidase has also