Here is the answer to where are the sensors for the arterial baroreceptor reflex located?
It belonged to the MCAT practice test.
Where are the sensors for the arterial baroreceptor reflex located?
- The sympathetic and parasympathetic nervous systems.
- Cardiovascular centers in the medulla oblongata.
- Carotid sinus and aortic arch.
The correct answer is below.
Arterial pressure sensors
The sensors of baroreceptor reflex are sensory nerve endings located under the outer membrane of the carotid sinus and aortic arch, called arterial baroreceptors.
Arterial pressure sensors do not directly sense changes in blood pressure, but rather sense the degree of mechanical stretch of the vessel wall.
As arterial blood pressure rises, the arterial walls are stretched more and the baroreceptors fire more nerve impulses.
Within a certain range, the frequency of afferent impulses of the pressure sensors is proportional to the degree of dilation of the arterial wall. In a cardiac cycle, as the fluctuation of arterial blood pressure, the afferent impulse frequency of the sinus nerve also produces corresponding changes.
Arterial baroreceptor reflex
There are abundant baroreceptor nerve endings in the carotid sinus and aortic arch under the adventitia of the vascular wall.
When arterial blood pressure is elevated, the carotid sinus and aortic arch baroreceptors are excited, and the impulses transmitted through the sinus and aortic nerves to the medulla oblongata cardiovascular nerve center are increased, causing the cardiovascular sympathetic center to be inhibited and the cardiac vagus center to be excited.
The effect is the heart rate slows down, the myocardial contractile force weakens, the cardiac output decreases, the blood vessel dilates, the peripheral resistance decreases, the result makes the elevated blood pressure drops back, which is called the antihypertensive reflex.
In contrast, when arterial blood pressure drops, the result of baroreceptor reflex regulation is an increase in blood pressure, known as the pressure-boosting effect.
Therefore, this reflex has a bidirectional effect on the regulation of blood pressure, which is a negative feedback regulation.
The physiological significance of the antihypertensive reflex is to buffer the sharp changes of arterial blood pressure and maintain the relative stability of arterial blood pressure.
What are the things that the arterial baroreceptors feel?
What the baroreceptors perceive is the tension of the blood vessel wall.
There are many afferent nerve tips in the walls of the whole adductor system, including atria, ventricles, arteries, and veins. When the wall of the tube is passively dilated, these nerve ends can sense mechanical tension stimulation and cause cardiovascular reflex.
The nerve tip located in the wall of the circulating high-pressure part (arterial) plays a role in monitoring the circulating pressure on the arterial side, so it is called arterial baroreceptor or high-pressure receptor.
The most important are the baroreceptors of the carotid sinus and aortic arch.
The appropriate stimulation of the carotid sinus and aortic arch receptors is the dilation of the dividend of the vessel wall and the blood pressure itself.
Within a certain range, the frequency of the afferent impulse is proportional to the degree of passive dilation of the vessel wall.
In addition, at the same blood pressure level, carotid sinus and aortic arch baroreceptors were more sensitive to pulsating pressure stimulation than to non-pulsating pressure stimulation, a feature that corresponded to pulsating changes in blood pressure in the major arteries.
Correct Answer
Here is the correct answer to Where are the sensors for the arterial baroreceptor reflex located?
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