welcome back to the Mr sin Channel last time we talked about the endocrine system today we are going to be going over unit 2 topic three of AP Psychology an overview of the nervous system and the neuron the nervous system is our body's primary information system for our thoughts voluntary actions and also our involuntary action think of the nervous system as a high-speed bullet train the nervous system is constantly sending signals at an extremely fast speed throughout your entire body this is how your body communicates and makes decisions all of your actions feelings and thoughts require your nervous system so you could say the nervous system is a pretty big deal the nervous system can be broken down into two main parts we have our central nervous system and our peripheral nervous system the central nervous system is made up of the brain and spinal cord this is the control center that gives orders to the rest of the body while the peripheral nervous system is all of the different nerves that Branch off from the brain and the spine this allows the nervous system to communicate with the rest of your body so for example when you decide to smash the like button on a YouTube video or when you consider subscribing to a YouTube channel it's your central nervous system your brain that is sending a message through the peripheral nervous system through the nerves in your hand and telling your hand muscles to move and press that button now at the start of this video I said that the nervous system is how your body communicates and if you're good at communicating with people that means you're not only good at speaking but also listening communication is a two-way streak the nervous system is similar while the central nervous system sends messages through the peripheral nervous system to tell the body what to do the the peripheral system can also send messages back when looking at the peripheral nervous system we can see that we can break it down into the sensory Division and also motor division the sensory division also known as the afren division focuses on conducting impulses from sensory stimuli to the central nervous system this means that the pns is taking information from your body and sending that information to your brain remember at the start of the video when I said the nervous system is like a high-speed bullet train while the afren neurons of the pns are the tracks the messages are being sent through that go straight to the brain and spinal cord this allows your body to constantly be informed about what's going on inside your body but also what's going on around your body all this information comes from your sensory receptors Your Eyes Ears Nose tongue and Skin So when you accidentally set your hand on a hot oven burner your sensory receptors in your hands are saying ouch and that message is traveling up through the afron pathways of your pns to your brain and it's telling you that you're in pain next is the motor division also known as the efr division of the peripheral nervous system signals here come from the brain and spinal cord and go out to the muscles and glands of your body through the efferent neurons these signals create motor or movement responses going back to our example of your hand on the burner as soon as the message gets to your brain your hand is burning your brain sends a message down the fer and Pathway to your hand to move your hand off the burner these messages are being sent so quickly you hardly have time to realize what's happening remember the sensory neurons also known as the afferent neurons send signals to the brain and spinal cord while the motor neurons and F eer at neurons send messages from the brain and spinal cord to the rest of the body the somatic nervous system or also known as the skeletal nervous system includes your skeletal muscles your movement and your five senses these movements happen consciously and voluntarily whenever you go biking play video games you are using your somatic nervous system you are consciously pushing the pedals down with your legs or pressing the buttons on your controller which is your brain sending signals to those muscles to move the autonomic nervous system controls your involuntary activities this system makes sure you keep breathing keeps your heart rate beating your stomach digesting and all those other wonderful bodily functions that happen in the background that you need to survive all of this happens without you having to consciously think about it the autonomic nervous system allows us to reach homeostasis it provides stability for our internal environment the autonomic nervous system has two divisions which work together especially in an emergency the first is the sympathetic division which is what gets your body mobilized and ready for action this is what makes your heartbeat faster your eyes dilate and your breathing increase it also slows down your digestion to allow for more energy to go where it's needed it's known as your fight or flight response the second is the parasympathetic division which is what relaxes your body this slows your heart rate increases your digestion and helps you focus on saving and storing energy this is commonly referred to as the rest and digest Okay so we've been spending a lot of time now talking about the central nervous system and also the peripheral nervous system and now we are going to start talking about the cells that make up these system systems the neurons and their helper cells gal cells gal cells are the most abundant cells in the nervous system and they support neurons through protection they also provide them with nutrients Galo cells do not process information meaning they do not send any messages or signals for your body neurons on the other hand are the basic functional unit of the nervous system neurons communicate with each other by using electrical impulses and chemical signals to send information throughout our nervous system let's take a minute and go over the different parts of the nerve cell the name of the cell body is called the Soma this house is the cell's nucleus the nucleus contains the genetic material including information for the cell to develop and other structures that allow the neuron to function extending outward from the Soma are dendroides which receive chemical information from adjacent neurons through receptor site the dendrites send this information towards the cell body the message then goes down the axon fiber this is the longest part of the neuron and it carries information away from the Soma and out through its terminal branches think of the axon as a long cable that allows the cell to send information away from itself to other cell when I say information is being sent down the axon it's sent in the form of an electrical impulse this is a process called an action potential we'll go more in depth into this process in our next topic review video so make sure you've hit that subscribe button so you don't miss it all right so we're almost done but I want to highlight a couple more important parts of the neuron first we need to go back to G cells and talk about how they can protect the neuron when it comes to protecting the neuron we have G cells known as Schwan cells which wrap around the axon and produce the milin sheet the mil sheath covers the axon and increases how fast the action potential travels down the axon and it also protects the axon from being damaged now there are gaps in the milein sheath which are called the nodes of ranir this is where the axon is exposed which helps promote the continuing action potential as the information and action potential progress down the axon it reaches the axon terminal it then has reached a meeting point between the two neurons this is called the synapse this is where the action potential releases neurotransmitters into the synaptic gap or CFT which is how information is further related to the receiving neuron this is how neurons talk to each other the synaptic gap is the space between the neurons specifically between the end of the axon terminal and the next neurons dendrite or cell body just like action potentials we get into the specifics of neurotransmitters and the synapse in future vide for now remember that the neurotransmitters are located at the end of the axon which is called the axon terminal and are released into the synapse so you can see that your nervous system is a pretty big deal this allows us to function and live the lives we live this video is just a quick overview of the nervous system in our next video we'll go into the neurotransmitters and the different types of neurons so make sure you hit that subscribe button so you don't miss out on any of that awesome content also if you're struggling with any of these different types of Concepts make sure to check out some of the resources in the description of this video and of course don't forget to answer the practice questions that have been on the screen and check your answers in the comment section below thank you so much for watching I'm Mr sin and until next time I'll see you online [Music]