 Hi, guys. Today we're going to talk about the autonomic nervous system. Before we start getting into the details of the autonomic nervous system, we are going to yet again review the entire, the organization of the entire nervous system just so we can keep perspective on where we're mapping our details. The details of the autonomic nervous system are going to include both visceral motor pathways and visceral sensory pathways. And so we're going to be able to put all that stuff together, but first we must draw our nervous system. And as always, we have a lovely brain and spinal cord to represent the central nervous system. As always, we must have some kind of stimulus that triggers the nervous system into action. The stimulus, we actually talked in the last lecture about all the possible stimuli and the mechanisms by which the stimulus can be translated into an afferent message. So there has to be some kind of receptor, some kind of sensory receptor, and that sensory receptor somehow either is an afferent neuron or is attached to an afferent neuron, but somehow sends the message into the central nervous system via an action potential. So somehow the stimulus gets translated into an action potential that gets sent to the central nervous system. We know that holy processing happens in the central nervous system. And then we mapped out a couple of options. One of our options for action was the somatic motor pathway, and that included all neurons that innervate skeletal muscle. And that's actually our next topic. So we're going to finish up today looking at the autonomic nervous system, and then we're going to dive into how skeletal muscle is involved in this whole process and how skeletal muscle functions. So today we're going to look at two different branches of the visceral motor pathway. And all visceral motor pathways, as we know, innervate either cardiac muscle, smooth muscle, or glands. And these are the details that we're going to flesh out today. We have two branches of the visceral motor nervous system, sympathetic and parasympathetic, and we're going to look at details, like what's exactly going on here. The other thing that we're going to talk a little bit about today is the fact that sometimes this afferent pathway or this receptor up here is a somatic sensory receptor, like all of the somatic sensory receptors we talked about in the last lecture, but sometimes it can be a visceral sensory receptor, and the visceral sensory receptor picks up something, some gut sensation that maybe you're not entirely conscious of, and same thing, that information can be sent to the central nervous system for processing. So in the next section, we're going to look at some specific visceral sensory receptors and some qualities that we can measure. We're going to look a tiny bit because I can't help it at a few places where we might integrate information in the central nervous system, and then the rest of the time we're going to spend focusing on the visceral motor half of the autonomic nervous system. How's that for a fun plan? Okay, let's do it.