 Now we're going to map our efferent nervous system onto this little diagram. And again, if you just had to take a wild guess right now, do it. Guess. Are you going to guess that we have different flavors of efferent information? And if you had to guess, like, what are those different flavors, would you guess that we have what? They're different motors. So we have somatic motor, somatic motor pathways. And who else? Dogs of a feather. We have visceral motor. We'll do it right here. Now the fact is that we also have interneurons doing their thing in the central nervous system, and we're not mapping those guys yet. There is no one pathway between the efferent information and the efferent information, so I'm not going to connect my efferent to my efferent right now. There is the exception of, like, a reflex. Then you know that the efferent... You know... you can map out for sure what efferent stimulus is going to follow what efferent pathway to stimulate, what efferent pathway to cause what action to take place. Whoa. But for the most part, most of the time, you never know. Sometimes you don't even know what your action is going to be. Well, I definitely often never know what my actions are going to be. Okay. If we wanted to map somatic motor, that's just conscious motor action. And a somatic motor pathway, look at what I just drew. My cell body is actually in the spinal cord. It's in the central nervous system, and I'm going to undo that because I don't want them connected right now. We'll make this a rather high level of spinal cord, somatic motor neuron. Traveling out, its cell body is in the central nervous system, and this is actually kind of beautiful in magic because all somatic motor neurons innervate skeletal muscle. Done. It's that easy. If a somatic motor fiber is traveling from the central nervous system to an effector, the effector is skeletal muscle. If the effector is skeletal muscle, the fiber that innervated it is somatic motor fiber. Does that work? So what is visceral motor? You may be a little sad, but there are three things that visceral motor pathways innervate, three effectors that are possible. Always ready, smooth muscle. If a neuron causes an action in smooth muscle, it's a visceral motor neuron. Smooth muscle, cardiac muscle. If a neuron causes an action in the heart muscle, it is a visceral motor neuron or glands. If the neuron causes an action of a gland, then it was a visceral motor neuron. Visceral motor gets a little bit more complicated because there are actually two flavors of visceral motor. We have one, which is I'm drawing it here on purpose and we'll talk about the details of this later, but this is a parasympathetic pathway. A parasympathetic pathway, notice, we still have a cell body. It's a motor pathway, it's a visceral motor. It has its cell body in the central nervous system. The information follows a path with two neurons. It's a two neuron series to get to my effector. And just for the heck of it, because cardiac muscle is one of my effectors in a visceral motor system, we're going to say that my effector here is the heart. Parasympathetic fibers innervate smooth muscle, cardiac muscle, or glands. And just because, I mean, you probably already know this, but parasympathetic nervous system causes like a decrease, a slow down, a relaxing. Life is good within parasympathetic fibers are activated. That's my other option. My other option, my little cute heart friends, that's you guys, is sympathetic. Again, it's visceral motor. We have a two neuron pathway. We actually innervate the same effectors, smooth muscle, cardiac muscle, or glands, but this time it's a sympathetic pathway. And a sympathetic pathway activates everything. This is the quintessential oh shit response. Probably shouldn't write that out in the universe, but that's how my brain thinks about it. If you have an oh shit response, that's your sympathetic nervous system activating. Notice that both of these are visceral motor, both of them are green. One of them activates the effector. The other one calms it down. All of these effectors are innervated by both sympathetic and parasympathetic fibers. We're going to spend a whole lecture talking about that, going into the details of the anatomy and the physiology of just the visceral motor system. Look at that pretty picture. I love that. Okay. You might think, dude, let's call it good. Maybe we should call it good, except in lab today. We're looking at slides of the nervous system. We're looking at the histology of the nervous system. And one of our slides is the spinal cord. In order to understand the slide that you're going to be looking at, you have to understand spinal cord anatomy. So we're not going anywhere until we talk about the spinal cord anatomy and cover ourselves for our lab today. So let's talk about the spinal cord next.