Carotid sinus

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Carotid sinus

The initial enlargement at the origin of the internal carotid artery (internal carotid artery ) is called the carotid sinus or carotid sinus (also called the bulb ) . In the vascular wall of the carotid sinus there are pressoreceptors (also called baroreceptors), i.e. receptors that register blood pressure in the blood vessel system .

The pressoreceptors respond to changes in arterial blood pressure, especially wall tension. When the pressure increases, nerve impulses are conducted via the carotid ramus of the glossopharyngeal nerve via the cardiorespiratoria of the solitary nucleus to the circulatory center in the medulla oblongata . From here, reflex activation of the parasympathetic nervous system and inhibition of the sympathetic nervous system slow down the heart rate ( bradycardia ) and lower blood pressure through vasodilation .

Pressoreceptors with the same function are also located on the aorta . These are combined with the carotid sinus as the sinuaortal system .

Clinical Aspects

The carotid sinus reflex ( carotid sinus pressure test , also Hering reflex , according to Heinrich Ewald Hering ) can be triggered by strong pressure from outside on the branching of the carotid artery . This leads to a reduction in heart rate and blood pressure; if it lasts for a long time, this can lead to cardiac arrest.

A pathologically increased (hypersensitive) reflex is called a carotid sinus syndrome . The cause is usually atherosclerosis ("hardening of the arteries") in the area of ​​the carotid sinus. Moving the head backwards can trigger a reflex response. In the carotid sinus syndrome, syncope or dizziness attacks occur due to insufficient blood supply to the brain. A distinction is made between the cardioinhibitory type , in which the drop in heart rate dominates, the vasodepressor type with a drop in blood pressure and the mixed type.

See also

Individual evidence

  1. ↑ FCAT - Federative Committee on Anatomical Terminology: Terminologia Anatomica. Thieme, Stuttgart et al. 1998, ISBN 3-13-114361-4 .
  2. ↑ Wolfgang Dauber: Feneis' picture lexicon of anatomy. Georg Thieme Verlag, Stuttgart 2005, ISBN 978-3-13-330109-1 , p. 232.
  3. ↑ Ulrike Bommas-Ebert, Philipp Teubner, Rainer Voß: Short textbook anatomy and embryology. Georg Thieme, Stuttgart, 3rd edition 2011, ISBN 978-3-13-151793-7 , p. 91.
  4. ^ Roche Lexicon Medicine. Elsevier Health Sciences, 2003, ISBN 978-3-437-15156-9 , pp. 978
  5. ↑ KA Anderson, A. Dröber, LE Anderson, U. Villwock: Springer guide Care. Springer-Verlag, 2nd edition 2013, ISBN 978-3-662-01099-0 , p. 513.
  6. ↑ Internal medicine. Georg Thieme Verlag, Stuttgart 2001, ISBN 978-3-13-128751-9 , p. 232.