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Encyclopedia > Carotid body

The carotid body is a small cluster of chemoreceptors and supporting cells located near the bifurcation of the carotid artery. It measures changes in blood pressure and the composition of arterial blood flowing past it, including the partial pressures of oxygen and carbon dioxide and is also sensitive to changes in pH and temperature. The chemoreceptors responsible for sensing changes in blood gasses are called glomus cells. While the central chemoreceptors in the brainstem are highly sensitive to CO2, the carotid body is a peripheral chemoreceptor that provides afferent input to the respiratory center that is highly O2 dependent. Below an oxygen partial pressure of 60 torr, the carotid body cells release dopamine and trigger EPSP's in synapsed neurons leading to the respiratory center. This event is mediated by a unique potassium channel that is responsive to the partial pressure of O2. The peripheral chemoreceptor's input is secondary to CO2 sensitive cells in the central chemoreceptors in healthy patients, but is the primary driver of ventilation in individuals who suffer from chronic hypercapnia (as in emphysema). A Chemosensor, also known as chemoreceptor, is a cell or group of cells that transduce a chemical signal into an action potential. ... In human anatomy, the carotid artery is a major artery of the head and neck. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ... The title of this article should be pH. The initial letter is capitalized due to technical restrictions. ... Temperature is also the name of a song by Sean Paul. ... A glomus cell is a peripheral chemoreceptor, located in the carotid bodies and aortic bodies, that helps the body regulate breathing. ... Hypercapnia (from the Greek hyper = above and kapnos = smoke) is a condition where there is too much carbon dioxide (CO2) in the body. ...


Image:carotid.jpg Image File history File links Carotid. ...


It gives feedback to the medulla oblongata via the afferent branches of the glossopharyngeal nerve (IX). The medulla, in turn, regulates breathing and blood pressure. The medulla oblongata is the lower portion of the brainstem. ... The glossopharyngeal nerve is the ninth of twelve cranial nerves. ...

Contents


Disorders

A paraganglioma is a tumor that may involve the carotid body. A paraganglioma is a rare neoplasm that can be found in the head and neck region and other less common areas. ...


How they work

The type 1 gloumus cells in the carotid (and aortic bodies) have hypoxia dependent K+ channels which close upon hypoxia. This creates a relative depolarisation and stimulates the afferent nerve fibres (CN IX in the carotid) to fire an action potential to the nucleus of the tractus solitarius.


See also

The aortic body is one of several small cluster of chemoreceptors, baroreceptors, and supporting cells located along the aortic arch. ... Control of respiration refers to the physiological mechanisms involved in the control of respiration (physiology). ...

External links

  • Respiratory physiology notes at Kirksville College of Osteopathic Medicine (Missouri)

  Results from FactBites:
 
Carotid Body Paraganglioma (May 1995) (1932 words)
The carotid body was first described by von Haller in 1743 and is a round, reddish-brown to tan structure found in the adventitia of the common carotid artery.
It is this close association with respiratory drive and the sympathetic nervous system response that have prompted investigation of the carotid body's role in disease processes such as obstructive sleep apnea and sudden infant death syndrome.
Histologically, the paraganglioma is similar to the normal carotid body except that clusters tend to be larger(Zellballen formation).
VI. The Arteries. 3a. 2. The External Carotid Artery. Gray, Henry. 1918. Anatomy of the Human Body. (4437 words)
Medial to it are the hyoid bone, the wall of the pharynx, the superior laryngeal nerve, and a portion of the parotid gland.
It then curves upward over the body of the mandible at the antero-inferior angle of the Masseter; passes forward and upward across the cheek to the angle of the mouth, then ascends along the side of the nose, and ends at the medial commissure of the eye, under the name of the angular artery.
It arises from the back part of the external carotid, near the commencement of that vessel, and ascends vertically between the internal carotid and the side of the pharynx, to the under surface of the base of the skull, lying on the Longus capitis.
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