Baroreceptor

Baroreceptor

Diagram of a baroreceptor

A baroreceptor is a type of sensory receptor that is sensitive to changes in blood pressure. These receptors are located in the walls of blood vessels, particularly in the carotid sinus and the aortic arch. Baroreceptors play a crucial role in the baroreflex, a negative feedback loop that helps maintain homeostasis by regulating blood pressure.

Function

Baroreceptors detect the stretch of the blood vessel walls, which corresponds to the pressure of the blood within the vessel. When blood pressure rises, the walls of the blood vessels stretch more, and the baroreceptors increase their firing rate. Conversely, when blood pressure falls, the walls stretch less, and the firing rate of the baroreceptors decreases.

The information from baroreceptors is transmitted to the central nervous system via the glossopharyngeal nerve (cranial nerve IX) from the carotid sinus and the vagus nerve (cranial nerve X) from the aortic arch. This information is processed in the medulla oblongata, which then adjusts the autonomic nervous system to maintain stable blood pressure. This can involve changes in heart rate, vascular resistance, and cardiac output.

Baroreflex

The baroreflex is a rapid response mechanism that helps to stabilize blood pressure. When blood pressure increases, the baroreceptors send signals to the medulla oblongata, which in turn activates the parasympathetic nervous system and inhibits the sympathetic nervous system. This results in a decrease in heart rate and dilation of blood vessels, lowering blood pressure. Conversely, when blood pressure decreases, the baroreceptors reduce their signaling, leading to an increase in heart rate and constriction of blood vessels, raising blood pressure.

Clinical Significance

Baroreceptors are essential for short-term regulation of blood pressure. Dysfunction in baroreceptor sensitivity can lead to conditions such as orthostatic hypotension, where blood pressure drops significantly upon standing, causing dizziness and fainting. Chronic hypertension can also affect baroreceptor function, leading to a diminished ability to regulate blood pressure effectively.

Related Pages

• Blood pressure
• Carotid sinus
• Aortic arch
• Glossopharyngeal nerve
• Vagus nerve
• Medulla oblongata
• Autonomic nervous system
• Parasympathetic nervous system
• Sympathetic nervous system
• Orthostatic hypotension
• Hypertension

See Also

• Chemoreceptor
• Mechanoreceptor
• Nociceptor
• Thermoreceptor