Explain how the body monitors blood pressure with baroreceptors and how the autonomic nervous system responds to maintain blood pressure by altering the heart rate and blood vessels.
Homeostasis of Blood Pressure:
Mechanoreceptors are a type of somatosensory receptors which relay the extracellular stimulus to intracellular signal transduction through mechanically gated ion channels. The external stimuli are usually in the form of touch, pressure, stretching and sound waves. They are present in the organs like skin, blood vessels, and the inner ear. The receptor (nerve cells) are sensitive to minor changes in the parameters and initiate a reflex action (autonomic nervous system) that resets the homeostasis by either stimulating or inhibiting the physiology of the associated organs. The homeostasis of blood pressure involves constant monitoring of the pressure of the blood flow in the heart muscles and larger arteries to maintain the normal blood pressure in the body. Some of the other types of receptors in the body are thermoreceptors (skin), chemoreceptors (taste) and photoreceptors (vision).
Answer and Explanation: 1
Baroreceptors are the type of mechanoreceptors located in large arteries like the carotid arch. They sense the pressure changes by responding to change in the tension of the arterial wall. The baroreflex mechanism responds to acute changes in blood pressure and is a fast response mechanism. The impulses are relayed to the vasomotor center of the brain. A sudden increase in blood pressure stretches the baroreceptors and the increased firing results in the vasomotor center inhibiting sympathetic drive and increasing vagal signal on the SA (sinoatrial) node of the heart. The SA node is slowed by acetylcholine and the heart rate slows to correct the increase in pressure. When the blood pressure of a person drops suddenly, for example standing up from a reclining position or standing up suddenly from a prolonged sunbath, the decreased blood pressure is sensed by baroreceptors as a decrease in tension and results in the decreased firing. This causes the vasomotor center to stimulate sympathetic activity in the heart and the blood vessels and decreases the vagal signal (parasympathetic effect on the cardiac SA node), causing an increase in heart rate.
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fromChapter 14 / Lesson 8
Learn about baroreceptors and the regulation of blood pressure. Discover how baroreceptors work to maintain consistent blood pressure in the body.