 In our last video we covered the gross anatomy of the spinal cord, now we're going to look at the cross-sectional anatomy of the spinal cord. So here we see a slice of the spinal cord, right in the middle you have the central canal, so that's going to be that empty canal or hollow canal full of cerebral spinal fluid that's continuous with the ventricles of the brain. And then just a big picture you see two main things here. You see the gray matter which surrounds that spinal cord, the gray matter is going to be where the nuclei are, so it's going to be where the cell bodies are plus the neuroglia, the support cells. So when I think of gray matter I think of information processing. So that's going to be the gray matter, the posterior or dorsal half of the spinal cord is sensory, so the posterior horns they are going to be sensory, and then the ventral or anterior half of the spinal cord is going to be motor, so that ventral horn is going to be motor. We'll talk about the lateral horn in just a moment. So that's the gray matter which is where the cell bodies are and information is being processed. The white matter all around that is white from the fat that myelinates most of our nerves. So white matter is going to be what's carrying information up and down the spinal cord. So gray matter think information processing, white matter think transport just like we did with the brain. The biggest difference is the brain has gray matter on the outside and white matter on the inside. The spinal cord has this butterfly shaped gray matter on the inside and the white matter on the outside. So here's a little more specifically what's going on. So these, you know, our cell bodies and their supportive cells are going to be grouped together in what are called nuclei. So the posterior gray horn of the spinal cord is going to be where you have somatic and visceral sensory nuclei. So somatic sensory information and then visceral sensory information are going to are going to travel to the posterior horn of the spinal cord and they're going to be the information is going to be traveling up the dorsal or posterior half of the white matter of the spinal cord to reach the brain if needed. The anterior horn. So the anterior gray horn is going to be where your somatic motor nuclei are. So information is going to travel down from the brain on the anterior half of the spinal cord. It's going to reach the somatic motor nuclei there and then it's going to control whatever effect or whatever, whatever muscle or organ it needs to control or this would be the muscles with somatic motor. Then you see the lateral gray horn there on the side. This is going to be only found in the thoracic and lumbar spine from T1 to L2, the same place your sympathetic nervous system is. And this is going to be visceral motor nuclei or as it says here, autonomic efferent nuclei. So it's going to control your cardiac muscle, smooth muscle glands, fat. These types of things are going to come from the lateral horn. All right, so that's the cross-sectional anatomy of the spinal cord and that's where all the different sensory and nuclei are. Now let's go ahead and look at a nerve. So our spinal nerves are called mixed nerves because they're a combination of sensory and motor. So you see there the blue, the dorsal or posterior half of a spinal nerve is going to be sensory. So the dorsal, notice the dorsal root ganglion is actually where the cell bodies of sensory nerves are. We talked about this before. Remember sensory neurons are unipolar. So since that cell body is in the middle, that's why you see this ganglion outside of the spinal cord. So the dorsal half of this nerve or the dorsal root is sensory. And remember that the dorsal root ganglion is where the cell bodies of your sensory nerves are. The motor neuron is going to be in from the ventral root. So the ventral half is going to be motor and they're both going to the, so the dorsal and ventral root are both going to travel out of the spinal cord and out of the inter vertebral foramen between the spinal bones. Then they're going to fuse together to become a mixed nerve or your spinal nerve and then they're going to go wherever they need to go. So where are the cell bodies? Hopefully you remember from earlier that motor neurons are multipolar with the cell bodies on the end. So the cell bodies of your motor neurons are actually there in the ventral root of the spinal cord. All right, that's plenty for the sexual anatomy of the spinal cord. I hope this helps. Have a wonderful day. Be blessed.