Autonomic vs somatic nervous system | Muscular-skeletal system physiology | NCLEX-RN | Khan Academy

Autonomic vs somatic nervous system | Muscular-skeletal system physiology | NCLEX-RN | Khan Academy

We can think of the
nervous system as split up into two other parts. There’s going to be an
autonomic nervous system branch. And as the name
kind of sounds like, this is your automatic control. That’s the involuntary
parts that we talked about from above. Beside that, there’s also going
to be a control that we exert. And so that’s going to be called
the somatic nervous system. So that’s something
that we control, somatic nervous system. Underneath the autonomic
classification, you can break this up
into two other parts. One is called the
sympathetic nervous system. And we sort of alluded
to that above when we were talking about the
sympathetic ganglia that were part of
involuntary control. In addition, we also have a
parasympathetic nervous system that sort of sits in a
checks-and-balances position with the sympathetic
nervous system. And that’s how we break this up. The somatic nervous
system is just the somatic nervous system. So it has just sort
of one function, and it’s trying to
control voluntary muscle. So the neurotransmitter
that we use here, which you may recall– and
I’ll put this in parentheses– is acetylcholine. And we abbreviate that
ACh for acetylcholine. What about the
neurotransmitters that are used by the sympathetic
and the parasympathetic nervous system? We actually sort of
know them already, at least for the
sympathetic nervous system. And we can come up with it. And the way you know them
is if you think about what the sympathetic
nervous system does. Because I’m sure you’ve heard
of this phrase called your fight and flight response. Fight or flight. And so that’s when you’re in
a dire situation and your body senses, uh-oh, I may
die at any second now. I need to do something
to get out of here. And so you activate the
sympathetic nervous system so that you can achieve
fight or flight. You start pumping adrenaline
through your body, and you get your
heart to beat faster so you can pump more
oxygen to your legs to help you run
quicker and get away. So that’s fight or flight. And so I mentioned
adrenaline, which is an endocrine hormone that’s
secreted to help with this. But it also has a
neurotransmitter friend that does the same thing. And so the
neurotransmitter friend that I’m going to write up
here, it’s not adrenaline, but it’s noradrenaline. Starts with an N. And
another term for that is norepinephrine. I’ll write it out. Norepinephrine. Or noradrenaline. And so that’s the
neurotransmitter that’s used by the
sympathetic nervous system. What about the parasympathetic
nervous system? Well, oddly enough it
actually uses the same one that the somatic
nervous system does. And the way that you can
sort of differentiate this from the sympathetic
nervous system is that, while the
sympathetic nervous system is for the super, hardcore,
intense moments where it’s fight or flight, the
parasympathetic nervous system is a little more chill. This is for rest and digest. So when you’re going to sleep
and you’re trying to relax so your heart rate can lessen and
your muscles and your heart aren’t contracting as quickly. Or if you just ate
a big meal and you need to digest that food, the
parasympathetic nervous system will tell the stomach
to churn that food up so you could digest
it in your intestines as you also propel it along
with the smooth muscle in there. So that’s achieved
by acetylcholine. All right? So that’s the two
major divisions of the central nervous
system, autonomic and somatic.

20 Replies to “Autonomic vs somatic nervous system | Muscular-skeletal system physiology | NCLEX-RN | Khan Academy”

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