 Hey everybody, Dr. O here. Welcome to the nervous system. So I'm just going to give you a quick overview here. We'll cover the branches of the nervous system in a separate video. We'll dive into some of these topics in more detail. But the nervous system is all the neural tissue in your body. And neural tissue can be broken down into two parts, two types. We have neurons, which are the cells that actually send and receive electrical impulses. We'll cover them later. And we have neuroglia, which means nerve glue. These are going to be the support cells that help the neurons do their job or protect them or build a framework for them, these types of things. So we have neurons and neuroglia. The key organs we're going to cover here with the nervous system are, you know, the brain and spinal cord are definitely going to be the big ones. So obviously we'll cover the brain and the spinal cord in great detail. But we also have sensory receptors. So receptors are a part of the nervous system because they are what trigger the signals that go towards your brain and spinal cord. So this could be like free nerve endings that are pain fibers. And then some we think about, think about like the special senses like your eyes and your ears. These are all going to be sensory receptors. And the last, you know, organ or structures we'll talk about will be the nerves that carry the signals to and fro, I guess. All right. So the two parts anatomically will break the nervous system down functionally in a separate video. But the two anatomical divisions of the nervous system is the central nervous system and the peripheral nervous system. Simplest way to look at this. The central nervous system is the brain and spinal cord. The peripheral nervous system is everything else, those nerves and receptors. So here we see the central nervous system. Its primary job is to process sensory data that travels towards the brain and spinal cord, whether that be a conscious activity or a reflex. And to coordinate motor commands that carry, carry information away from the brain and spinal cord. And then we do have, since we have this massive brain, this massive frontal lobe, then we have what are called your higher order functions, memory, you know, learning, intelligence, emotions. These are the kind of things that occur in the central nervous system. The peripheral nervous system is going to be then the transport mechanism, basically. The peripheral nervous system would be those nerves and the receptors we talked about. So their job is to deliver sensory information towards the central nervous system. So to send sensory information from my fingers and toes towards my brain and spinal cord. And then to carry out, carry the motor commands away from my brain and spinal cord. So we'll talk about reflex arcs and neural arcs and all that. Okay. All right. A couple more terms here. You'll notice that groups of neuron cell bodies are going to be called a nucleus in the central nervous system. So it doesn't really matter yet, but we'll cover the basal nuclei when we get to the brain. And then a cluster of neuron cell bodies in the peripheral nervous system is called a ganglion. So we'll talk about the dorsal root ganglion and we'll talk about some other ones as well. Then we have any bundle. So a neuron is a single nerve cell, but when you bundle them together in the peripheral nervous system, they are called nerves. So we have two types of nerves that we'll primarily focus on. We'll really only focus on which will be your cranial nerves, which are connected to the brain. We'll cover the 12 pairs of cranial nerves. And then we have the spinal nerves, which are the nerves that connect to your spinal cord. So we'll cover tons of them later. But that's a nerve, a bundle of axons in the peripheral nervous system. In the central nervous system, they're called a tract. So it could actually be the same bundle. That's why I had this example here. You see the eye and the brain. Because look at those optic nerves. As they leave the retina of the eye and they travel towards the brain, but they're still part of the peripheral nervous system, it is called the optic nerve. But then they're at the optic chiasm where you see that crossing over. That's what chiasm, this chiasm, what occurs there. Then this same bundle of axons is now called the optic tract. So we use the word nerve in the peripheral nervous system and we use the word tract in the central nervous system. Okay, that's plenty for now as an introduction to some basic terminology and the basic functions of the two anatomical divisions of the nervous system. We're just getting started. We got a lot of ground to cover. This is the most complex organ system that we have. I hope this helps. Have a wonderful day. Be blessed.