Sympathetic / Parasympathetic Nervous System

[letaps]

What nerve innervates the sympathetic nervous system?..kinda like how the vagus nerve innervates the parasympathetic...

Thanks

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[rotatedline]

What nerve innervates the sympathetic nervous system?..kinda like how the vagus nerve innervates the parasympathetic...

Thanks

There isn't a single nerve that innervates the entire sympathetic nervous system. It's a 'chain' of ganglions that respond to stimulation from different spinal nerves. If your having difficulty remembering which is which, a pharm. prof had my class think of it this way: sympathetic=dry and parasympathetic=wet. In other words, your sympathetic nervous system decreases mucosal secretions, increases hr, etc. through the release of norepinephrine. Para increases gut motility, bronchial secretions, vasoconstriction, decreased hr, etc. It has always seemed to work for me.

 

[linkin06]

sympathetic - fight or flight
parasympathetic - rest and digest

 

[sportsfreak]

from my understanding...

parasym---vagus nerve
sym-------upper thoracic ganglia

 

[matth87]

What nerve innervates the sympathetic nervous system?..kinda like how the vagus nerve innervates the parasympathetic...

Thanks

The vagus nerve does not "innervate" the parasympathetic nervous system but rather it is part of the parasympathetic nervous system. It release neurotransmitter acetylcholine onto the heart to slow the contractions. The vagus nerve innervates the heart and is part of the parasympathetic nervous system.

The sympathetic nervous system preganglionic neruons innervate the adrenal gland to cause the release of ephinephrine (adrenaline). It also is responsible for the adrenergic tone which is important in peripheral resistance and the partial contraction of aterioles to create a basal level of pressure. Norephinephrine is responsible for the adrenergic tone.

Let me know if you have any other questions.

 

[FutureInternist]

from my understanding...

parasym---vagus nerve
sym-------upper thoracic ganglia

This may be too much for the MCAT but....
Parasym -

• Within the head --> CNs III, VII & IX
• From neck to splenic flexure --> CN X
• Splenic flexure to colon (including gonads) --> S2 - S4
• Hence PNS also called Cranio-sacral
  

Sym - All thoracic & lumbar ganglion (hence also called Thoraco-lumbar)