The impact of the sympathetic nervous system on blood vessels

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Discussion Overview

The discussion revolves around the role of the sympathetic nervous system in the regulation of blood vessel behavior, specifically focusing on vasoconstriction and vasodilation. Participants explore various physiological responses and mechanisms, addressing both theoretical and practical implications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants express confusion over the contradictory information regarding the sympathetic nervous system's role in blood vessel regulation.
  • It is suggested that certain blood vessels, such as coronary and pulmonary vessels, can experience dilation due to catecholamines, although this may not apply universally.
  • There is mention of vessels being constricted while simultaneously becoming sensitized to nitric oxide (NO), potentially enhancing vasodilation when necessary.
  • Some participants note that terminology can be imprecise, with "sympathetic" sometimes used incorrectly to refer to both branches of the autonomic nervous system.
  • One participant emphasizes that the effects of the sympathetic nervous system can vary depending on the organ in question, with dilation occurring in organs associated with stress responses, while perfusion to the intestines is reduced.
  • There is a suggestion that local mechanisms, such as NO regulation, play a significant role in peripheral blood flow, independent of neurological influences.
  • Participants critique the reliability of online resources for scientific information, suggesting that Wikipedia may be a more reliable starting point for such topics.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the specific mechanisms or effects of the sympathetic nervous system on blood vessels, with multiple competing views and uncertainties remaining in the discussion.

Contextual Notes

Some claims depend on specific contexts, such as the type of blood vessel or organ involved, and there are unresolved questions regarding the accuracy of terminology and the interpretation of physiological responses.

samy4408
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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?
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samy4408 said:
"...can be..."? Could you please continue the quote or elaborate?

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:
"...can be..."? Could you please continue the quote or elaborate?

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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Is it from a specialty textbook? (like e.g. neurology?)
 
no, it is the first lines that come off when I typed "which nervous system is responsible for vasodilation"
 
Godot_ said:
"...can be..."? Could you please continue the quote or elaborate?

Certain vessels can get dilated by catecholamines - e.g. coronaries, and 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.
thanks, interesting information but do you have the final answer?
 
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.
 
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nice! thanks, man.
 
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