Anatomy of the Autonomic and Voluntary Nervous System (Nursing)

00:01 Now, we've eluded to this difference a little bit already but now, we're really going to distinguish between what we consider the somatic nervous system versus the autonomic nervous system.

00:13 So, the autonomic nervous system is automatic. It's the unconscious or involuntary regulation of things.

00:23 Generally, things we can't consciously control like heart and things like that.

00:30 Now, these are going to be innervated by very different types of nerves than the rest of the body and they're going to have, like a lot of ones preganglionic neurons that are going to be myelinated like a lot of nerves.

00:45 But then, they're going to meet at a ganglion and have a second nerve, so, a post-ganglionic neuron is going to be unmyelinated and that's what's going to attach to whatever it's trying to have an impact on, for example, the heart.

01:00 And that's going to be quite a bit different, even within the autonomic system, whether we're talking about Sympathetic or parasympathetic.

01:07 But in contrast, the somatic is the nervous system you're probably familiar with.

01:13 It's the conscious or voluntary regulation. Things like you want to move a muscle, you think about it and you move that muscle. That's the somatic nervous system.

01:21 That's generally stuff like skeletal muscles. And that's where we're going to have just a really long somatic motor neuron really coming pretty close to the spinal cord and having a very long course until it reaches that muscle, without this sort of, like, ganglion floating out somewhere in the body.

01:42 But if we look at the autonomic system in greater detail, we see it's broken down even further into parasympathetic and sympathetic nervous system.

01:53 So, the parasympathetic nervous system, sometimes also called craniosacral because the areas that control them are either in the cranium or the sacrum, so, a very superior, very inferior. And that's where these parasympathetic nerves are going to originate from. And what they're going to do is have a very long pre-ganglionic fiber and then, they're going to synapse at a ganglion that's very close to whatever organ it's trying to have an effect on.

02:25 And then, have a very short post-ganglionic section.

02:29 And parasympathetic is generally thought of as rest and digest, sort of the slower type of the autonomic system.

02:40 Conversely, the sympathetic nervous system is going to be confined the areas sort of in between craniosacral.

02:47 So, it's really going to be called something thoracolumbar, we say.

02:52 With those preganglionic fibers originating in that portion of the spinal cord.

02:58 And they're kind of going to be the opposite.

03:00 So, they're going to have a short preganglionic stretch and synapse close to the spinal cord.

03:06 Then, have a really long post-ganglionic course.

03:11 And functionally, it's going to be the opposite of parasympathetic as well.

03:15 So, the sympathetic nervous system is really that fight or flight type autonomic nervous system that you probably heard of before and that's going to be very opposite the rest and digest.

03:27 It's going to be about things like increasing heartrate and increasing blood flow and getting things going for, as the name applies, either fighting or fleeing from some sort of danger response.