 Hey everybody, Dr. O here. In the first video we talked about the anatomical divisions of the nervous system. The central nervous system which is the brain and spinal cord, peripheral nervous system which is everything else. Now we're going to look at the functional divisions of the nervous system. So we're not going to worry about the central nervous system anymore. We're going to look at the functional divisions of the peripheral nervous system. Now the first two key words I want you to learn here are the afferent versus the efferent divisions. So afferent means towards. So the afferent division is a division that's carrying information from out in the peripheral nervous system towards the central nervous system. So that's going to be up here on the screen, that's going to be your sensory division. Your sensory information has to travel towards your brain and spinal cord. The efferent division means away from. So the efferent division is going to carry information away from your brain and spinal cord out to your body. So the efferent division is the same as the motor division. So when I say sensory division or afferent division, I mean the same thing. When I say motor division or efferent division, I mean the same thing. So just keep that in your head that obviously sensor information has to travel towards your brain. If I touch something hot, that information has to travel towards my brain. But when I pull my hand away, when my brain tells my hand to move, that information has to travel away. All right, so that's afferent versus efferent. And as you can see here, we have the sensory and motor divisions. So the sensory division can be broken down into the visceral sensory division, which is going to be visceral means organs. So your visceral sensory division would be more things like vision or really your organs like your thoracic and abdominal pelvic organs, whereas somatic means body. So somatic sensory division would be more what we're thinking about your touch, pressure, physical sensations, and then things like vision and that. So visceral sensations are a thing. Your organs don't have as many sensory receptors as your fingertips, for example, but they do have some and you can feel some things with your organs. So visceral sensory division, think organs, somatic sensory division, think your physical body. And then we have your visceral and somatic motor division. So your somatic motor division is what controls your skeletal muscle. And then visceral motor division, we're going to break down, let me go to the next slide here. So a little different one, same kind of information. Your PNS is broken down into your somatic nervous system or your somatic motor division, which controls your skeletal muscles, both voluntary control and involuntary control with reflexes. And then we have the autonomic nervous system. So your somatic nervous system controls skeletal muscle, your autonomic nervous system controls cardiac muscle, smooth muscle, glands and fat. You don't often see that one, but fat is under control of the autonomic nervous system. So autonomic, I think automatic. This is like subconscious control of these structures. And then we'll have a whole chapter on this later, but the autonomic nervous system can then be further broken down into the sympathetic and parasympathetic divisions. So your sympathetic division, you've probably heard of the fight or flight response, a better way to say it might be fight, flight or freeze, but the sympathetic nervous system is excitatory. It's all about mobilizing energy and mobilizing your body. You're either going to run from a threat or you're going to fight it. So the sympathetic system is all about pumping your body up for physical action. The parasympathetic system, I like to call it rest and digest. Sometimes you hear it called rest and repose or different things, but rest and digest. Your parasympathetic system is all about conserving energy and restoring you, building you back up. So instead of mobilizing energy, it's going to be storing it. Instead of increasing your heart rate and your blood flow, it's going to be decreasing them. So we'll cover all that later. So these are the functional divisions of the nervous system. One more term or phrase I want you to know about before we're done here. Your digestive system does have its own division called the enteric nervous system. So autonomous subconscious control of things like reflexes that occur inside your gut. There's tons of nervous system input coming from the autonomic nervous system, but it can control, it can actually operate independent of your brain and spinal cord. That's why it's a separate division. There's about as many neurons in the enteric nervous system as there is in your spinal cord. So it's very important. I just wanted to make sure that you've heard that terminology because you're hearing so much more about it now when you talk about gut health and these types of things. Okay. So now with the first video, we covered the anatomical divisions of the nervous system. Now we've covered them functionally. I hope this helps. Have a wonderful day. Be blessed.