Hello and welcome to another episode of Interactive Biology TV where we're making biology fun. My name is Leslie Samuel and in this episode, episode 63, we're going to take a step back and we're going to talk about the divisions of the nervous system. So let's get right into it.
Now if you go all the way back to episode number one, we spoke about the nervous system. And we said that the nervous system is basically the control center of the body. And what we're going to do is we're going to take this and we're going to look at the different divisions within the nervous system.
First, we have the central nervous system and we have the peripheral nervous system. So these are the two systems that we can divide the nervous system into. Now the central nervous system, that is the processing center of the nervous system.
A lot of processing happens here, and the peripheral nervous system is what connects the central nervous system to the limbs and the organs. So we have the processing in the central, and then we have the peripheral nervous system, and these work together very well. Now let's take the central nervous system and divide that. That can be divided into the brain and the spinal cord.
Now the brain... That's the center of the nervous system. This is where most of the processing is happening. This is the part that's found within the skull. And this is where things like thought and emotion, coordinating the body's activities, all of that stuff happens in the brain.
And then, of course, we have the spinal cord. And the spinal cord sends signals to and from the brain, to and from the rest of the body. So it's connecting the brain to the rest of the body, basically. sensory signals come into the spinal cord and motor signals go out from the spinal cord. And we're going to talk about those as we deal with the peripheral nervous system.
So let's head on over there right now. The peripheral nervous system consists, once again, of two parts. That's the somatic nervous system and the autonomic nervous system. Let's talk about the somatic first. The somatic nervous system is where we're going to get...
control of voluntary activities and this is where skeletal muscles are involved. So if for example I want to walk, I need to contract the muscles in my legs and that is a voluntary activity that is controlled by the somatic nervous system. If I want to smile, I need to control the muscles in my face.
By the way, it takes less muscles to smile than to frown but I'm sure you know that. So this is all in the somatic nervous system. And then, of course, we have the autonomic nervous system, which is not voluntary.
This is the involuntary things that happen in the body. So it controls visceral functions like heart rate, respiration rate, digestion. Those things you don't need to think about. They just happen.
They are involuntary. And that is under the control of the autonomic nervous system. Now, we can take the autonomic nervous system and of course we can divide that into two parts. We have the sympathetic nervous system and the parasympathetic nervous system.
Now, the sympathetic nervous system that is involved in the fight-or-flight response. So, it's what happens to your body when your body is under stress. Things like increasing your heart rate and respiration rate.
Anything that you're... increasing. This is usually under the control of the sympathetic nervous system. So if you go for a nice long jog and your heart rate starts increasing and your respiration rate increases, that is under the control of the sympathetic nervous system. And then of course we have the parasympathetic which is opposite to the sympathetic and this is involved during rest and digest activities.
So it's the opposite of under stress. It's when there's rest, you're slowing things down, you're relaxing. That is more parasympathetic and these are both under the autonomic nervous system. So there we have it.
Those are the divisions of the nervous system. I hope that was clear to you. That's pretty much all I want to cover in this video.
As usual, I want to invite you to visit the website. You know it. It's at interactive-biology.com and there you can get other biology videos and resources to help make biology fun.
This is Leslie Samuel, and I'll see you in the next one.