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Hello, I have some trouble understanding the role of the sympathetic nervous system in vasoconstriction and vasodilatation of blood vessels, I searched and found contradicting resources, does anyone have the right answer?
The impact of the sympathetic nervous system on blood vessels
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- Thread starter samy4408
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- Blood Impact Nervous system System
In summary, the sympathetic nervous system regulates vasoconstriction and vasodilation of blood vessels. Certain vessels can get dilated by catecholamines, which makes sense physiologically. Intestinal perfusion is reduced, as is the global muscle arteriolic sphincter.
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"...can be..."? Could you please continue the quote or elaborate?samy4408 said:
Certain vessels can get dilated by catecholamines - e.g. coronaries, pulmonary vessels (IIRC). Which does make sense, physiologically. Also I seem to remember that, while on the one hand the vessels are constricted, they get sensitized to NO, so if need be, the vasodilation gets amplified a bit.
Also, sometimes the wording can be sloppy, using "sympathetic" when the author actually means both brances of the vegetative nerve system.
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Godot_ said:
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Is it from a specialty textbook? (like e.g. neurology?)
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no, it is the first lines that come off when I typed "which nervous system is responsible for vasodilation"
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thanks, interesting information but do you have the final answer?Godot_ said:
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Depends on where exactly (i.e. at which organ) you look.
Vessels in organs relevant to sympathicus-associated stuff - fight, flight, fright - will get dilated. Like e.g. heart and lung. Might be true for spinal motoneuron vessels, too...
Intestinal perfusion, however, is reduced, as is the global muscle arteriolic sphincter - and overridden by the local NO-regulation. (Which, BTW, is the most relevant mechanism in the periphery, paracrine, and completely free form any neurological interference.) Because what use is having your arms full of blood when running is your choice.
Also, as a take-home-message: Google pretty often pretty much sncks at auto-answering natSci stuff. Wikipedia would be a better starting point.
Vessels in organs relevant to sympathicus-associated stuff - fight, flight, fright - will get dilated. Like e.g. heart and lung. Might be true for spinal motoneuron vessels, too...
Intestinal perfusion, however, is reduced, as is the global muscle arteriolic sphincter - and overridden by the local NO-regulation. (Which, BTW, is the most relevant mechanism in the periphery, paracrine, and completely free form any neurological interference.) Because what use is having your arms full of blood when running is your choice.
Also, as a take-home-message: Google pretty often pretty much sncks at auto-answering natSci stuff. Wikipedia would be a better starting point.
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nice! thanks, man.
1) How does the sympathetic nervous system affect blood vessel dilation and constriction?
The sympathetic nervous system plays a significant role in regulating blood vessel diameter through the release of noradrenaline. This hormone causes smooth muscle cells in the vessel walls to contract, resulting in vasoconstriction and a decrease in vessel diameter. In contrast, the absence of sympathetic activity leads to vasodilation and an increase in vessel diameter.
2) What are the physiological effects of increased sympathetic activity on blood vessels?
Increased sympathetic activity can cause vasoconstriction in blood vessels, leading to an increase in blood pressure. This is due to the narrowing of vessel diameter, which creates more resistance to blood flow. Additionally, increased sympathetic activity can also decrease blood flow to non-essential organs such as the digestive system and skin, redirecting it to essential organs like the heart and brain.
3) How does stress affect the sympathetic nervous system's impact on blood vessels?
When we experience stress, our body's sympathetic nervous system is activated, causing an increase in heart rate and blood pressure. This increased sympathetic activity also leads to vasoconstriction in blood vessels, which can contribute to hypertension and other cardiovascular issues.
4) Can the sympathetic nervous system's impact on blood vessels be controlled?
While the sympathetic nervous system is an automatic response system, it can be controlled to a certain extent through relaxation techniques such as deep breathing, meditation, and exercise. These activities can help decrease sympathetic activity and promote vasodilation in blood vessels, leading to a decrease in blood pressure.
5) What are the long-term effects of chronic sympathetic nervous system activation on blood vessels?
Chronic activation of the sympathetic nervous system can lead to sustained vasoconstriction in blood vessels, which can increase the risk of developing cardiovascular diseases such as heart attack and stroke. It can also contribute to the development of hypertension and other related conditions. Therefore, it is essential to manage stress and maintain a healthy lifestyle to prevent long-term impacts on blood vessels caused by chronic sympathetic activity.
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