 So now let's look at structures that arise from the diencephalon. There are three. Three. That's nice. Let's make a list of them right now. First we have the epithalamus, except I don't want to use this fun color for the epithalamus. I'm going to use the fun color for the hypothalamus. Isn't that a fun color? The hypothalamus is one of them. The epithalamus is another. And what do you suppose? Epithalamus, hypothalamus. Don't we need the thalamus? Yes. And all of these guys, thala, oops, musts. And all of them come from the... I'm waiting for you to say it. Just kidding. Diancephalon. Well, not really. You probably all did say it, didn't you? You guys are so awesome. So let's talk about the epithalamus first. I don't even know if that was what I really wanted to talk about first, but look, there's one structure. All of these are as complicated as we want to make them. So we are going to definitely leave out some stuff. And we're going to know one epithalamic structure, one. And that would be the pineal gland. And the pineal gland is a gland, a structure that produces melatonin. And I'm going to color it in with green. Rah, thur. I would say this general area is epithalamus, but all we need to know is the pineal gland. The pineal gland produces melatonin. It's actually associated with light and dark cycles. There are fibers that come directly from your eyeball to your pineal gland, giving the pineal gland information about how light and bright it is. Some critters still have, like, connections, light-sensitive connections on the top of their heads, like some lizards or something, have a light-sensitive connection on top of their heads that feed information to the pineal gland that, again, about light and dark cycles. You don't have one of those. Your pineal gland gets its information from your eyeballs. The, let's do the hypothalamus next. The hypothalamus was a super cool color. And I'm going to tell you how I have to find the hypothalamus in Wendy Land. First of all, I have to find the pituitary gland. So do not be mistaken. I'm not coloring the hypothalamus. I'm coloring the pituitary gland. The pituitary gland is a very important gland, makes a lot of very important hormones. We'll deal with that in physiology. But the pituitary gland is literally attached to the hypothalamus. Do you see, carefully now, okay, we'll do it in more of an orangey, do you see my little tissue attachment? That attachment is called the infundibulum. The infundibulum literally connects the pituitary gland, which is a critical gland for homeostasis and healthy physiological functioning of your body, to the hypothalamus. Once I've found the pituitary and the infundibulum, I know it's connected to the hypothalamus. So look at my hypothalamus. It's this area right in here. Does that work for you? Now we have epithalamus with the pineal gland. We have the hypothalamus attached to the pituitary gland through the infundibulum. And then we can attempt to grasp the thalamus. Now the thalamus, I'm going to go, oh, it's about her, but it kind of goes bumping up into her. But look, you could take out. You could peel off all the cerebrum. And then can you imagine that you would have, like, a structure sitting, like, peel off all the cerebrum and now you've got a structure that's sitting there. And that's how I best visualize the thalamus. So actually, I think I took it this way. Surprise. This thing. What? Are you kidding? This is the thalamus. What's right there is the thalamus. And if you imagine that sticking up inside, oh, a brain, don't you go there. That thing is actually, like, right in here. If we sliced it down the middle, can you see how I miss the bump? The bump is deep in there. Can you visualize that? In the brain lab, you can actually be able to dissect sheep brains. And if you're careful, you can peel off the sheep's cerebrum and you can find this whole structure, which is your little brain stem with your midbrain-ish zone attached to it. I think that's helpful for visualizing the thalamus. Now, what do they do? Well, we already talked about the epithalamus and what it does. I'll tell you what the thalamus does. This is basically the gateway to consciousness. I think of the thalamus as, like, this little guy who's sitting in a booth saying to everybody that's coming through, yeah, no, you're not important. Scram, we don't have time for you. No, no, we definitely don't need to be aware of the color of the wall right now. That's irrelevant information. Because think about how much information your body is constantly, how much afferent information your body is inundated with, like, constantly. And if you were aware of all of it, I mean, you'd never be able to study anywhere, anywhere, like, ever, because you'd hear your kids out there and you'd hear the bird on the tree and you'd hear the squirrel jump through the window and, like, you could never focus because all that information would be coming into your brain constantly. Your thalamus says, this is worthy, this is not worthy, and basically decides what goes to your cerebrum for conscious processing. If you think about this, your thalamus has, I don't know, I just read it, like, 12 different nuclei in it, nuclei. It has 12 places where cell bodies are aggregated. So they're receiving information from somewhere and those cell bodies aggregate in the thalamus and the thalamus decides that information came in. Do we pass it on to the next place in the brain or do we just call it quits and stop the information right there? Most information gets stopped. There is no need to be conscious of most of the sensory stimulus that comes, that affects you or stimulates you. There's no need to get so stimulated, settle down. Instead, the thalamus will take care of that. Hypothalamus, hypothalamus, holy homeostasis. Your hypothalamus is basically regulating the whole thing. It's not necessarily keeping you alive but it's regulating all your autonomic nervous system, your endocrine system, and it's regulating your endocrine system because it's connected to the pituitary gland, body temperature, it controls emotional behavior. What? Food intake? Dude, you got to be kidding me. And water intake, like, it decides whether or not you're thirsty or not and tells you to have a drink of water because you're thirsty, don't you get dehydrated? Dude, the hypothalamus does everything. Now, are you comfortable? I am. I think we did everything. All right, let's go talk about the mesencephalon.