Carotid sinus

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In human anatomy, carotid sinus is a dilated area at the base of the internal carotid artery which is superior to internal carotid and external carotid bifurcation at the superior threshold level of the thyroid cartilage. The carotid sinus extends from the bifurcation to the "right" internal carotid artery. Carotid sinus is sensitive to changes in pressure in arterial blood at this level. This is a major baroreception site in humans and most mammals.

Video Carotid sinus

Structure

Carotid sinus is a reflex area of ​​the carotid artery, which consists of various nerve receptors for baroregulation (regulation of body pressure synchronized with external conditions).

Maps Carotid sinus

Function

The carotid sinus contains many baroreceptors that serve as "sampling areas" for many homeostatic mechanisms to maintain blood pressure. The carotid sinus baroreceptors are innervated by the sinus nerve, which is the cranial nerve branch IX (glossopharyngeal nerve). The glossopharyngeal synapses in nucleus tractus solitarii (NTS) are located in the medulla oblongata of the brainstem. NTS indirectly modulates the activity of sympathetic and parasympathetic (vagal) neurons in the medulla and the pons through the hypothalamus. These neurons then regulate the autonomic control of the heart and blood vessels. The aortic bending baroreceptor is innervated by the aortic nerve (Nerve of Cyon), which joins the CN X (vagus nerve) and moves to NTS.

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Clinical interests

These are sensitive sites of the body because stimulation can induce large-scale reflex effects throughout the body. It can be used therapeutically in treating resistant hypertension with baroreflex activation. Physical attacks at this point, resulting in a large baroreflex activation can lead to dramatic decreases in blood pressure and cerebral ischemia.

Disease

Carotid sinus often has atherosclerotic plaques due to impaired hemodynamics (low wall shear stress, reversal/recirculation flow). Because this plaque, if large and unstable, affects ischemic stroke and transient ischemic attack, carotid endarterectomy is often performed for prophylaxis.

Carotid sinus can be sensitive to manual stimulation, a condition known as carotid sinus hypersensitivity, carotid carotid syndrome or carotid sinus sync, where manual stimulation causes major changes in heart rate and/or blood pressure. This is classically present as a "faint" patient (actually presyncope) on several occasions when shaving, or in other ways in contact with their carotid sinuses.

Carotid sinus syndrome is a temporary loss of consciousness that sometimes accompanies convulsive convulsions due to the intensity of the carotid sinus reflex when pressure is formed in one or both carotid sinuses.

Treatment of resistant hypertension

Baroreceptor stimulation of the carotid sinus can be used to treat resistant hypertension through baroreflex activation. Tools such as pacemakers can be implanted to stimulate chronic electrical receptors, which are found to lower blood pressure up to 15-25 mmHg.

Carotid sinus massage

Carotid sinus massage, carotid sinus massage is used to diagnose carotid sinus syncope and is sometimes useful for distinguishing supraventricular tachycardia (SVT) from ventricular tachycardia. Like the valsava maneuver, this is a therapy for SVT. This is less effective than SVT pharmaceutical management with verapamil or adenosine although it is still the first line of preferred treatment in stable hemodynamic patients

Carotid sinus reflex death

Carotid sinus reflex death is a potential etiology of sudden death in which manual carotid sinus stimulation is thought to cause a strong glossopharyngeal nerve (Vagus nerve to arch aorta baroreceptors) impulses leading to terminal cardiac arrest. Carotid sinus reflex death has been shown as a possible cause of death in cases of strangulation, hanging and autoerotic strangulation, but such deduction is controversial. Studies have also shown that carotid sinus reflex can be a contributing factor in other mechanisms of death by reducing blood pressure and heart rate, especially in the elderly or in people suffering from carotid sinus hypersensitivity. Carotid massage may also produce thrombus, or some plaque. This can cause a number of life-threatening effects, including stroke.

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In the martial arts and self defense

Carotid sinus stimulation through slap or strike, to induce (usually temporarily but occasionally deadly) loss of consciousness is an effective self-defense technique, and is often taught in martial arts such as karate and Krav Maga.

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See also

• Carotid body
• Baroreflex

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References

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Additional Images

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External links

• lesson5 at The Anatomy Lesson by Wesley Norman (Georgetown University) ( livingneck )

Source of the article : Wikipedia