 So you thought we were done with the nervous system and what you will see in this last section of anatomy is that we're pretty much not done with anything. The nervous system and the endocrine system, because they're integrators, they are involved in all the body systems. So remind yourself about the hypothalamus and where it's located. We have a nice little view here of a sagittal slice of this fella's head. And you can see your structures, cerebrum, cerebellum, there's the pons. You can remind yourself about where the hypothalamus is, below the thalamus. This is actually the thalamus. Hypothalamus is this blue thing, color, hypothalamus. And these images are from the open stacks textbook, which is actually free, open resource, which is awesome. What I want you to also see, because again, why are we talking about a nervous structure here, I want you to see the pituitary gland. The pituitary gland, I'm pasting it, I'm not pasting anything, I am tracing it. That's the word I wanted. I'm tracing the pituitary gland and I hope you can see that the pituitary gland is connected to the hypothalamus by this kind of orange structure. What is that orange structure? You know that thing. You know you know that thing. It's kind of one of my favorite structures. I mean, I love this whole area over here. That orange thing is the infendibulum, infund, so fun, dib, way dibbing, you loom. Okay, I just am going to settle down there. You remember the infendibulum. In fact, when I'm looking at a slice of human head, I find the hypothalamus by first finding the pituitary. Remember pituitary? Where it's sitting down in the seletursica of the sphenoid bone. The pituitary sits down in there and you can find the infendibulum. It's a little piece, little stalk of tissue and if you follow that stalk of tissue up, the next place you're going to be is hypothalamus. Why? They actually have an anatomical connection between them. The hypothalamus is anatomically connected to the pituitary gland. You know why? It's like a private message line. Like the hypothalamus says, pituitary, you're really important. In fact, the pituitary gland is considered the master gland of all glands in the endocrine system. But the hypothalamus has an anatomical connection to the pituitary and basically calls the shots. By calling the shots, ultimately the hypothalamus is in charge of the endocrine system, which is really interesting. So there is an anatomical thing that we can find in here because there's a couple of things that you need to know about the hypothalamus. First of all, hypothalamus controls the pituitary gland and if you notice, what do you notice about my pituitary gland? It's color-coded and there's two colors. That's because the pituitary gland is an anterior portion and a posterior portion. So I'm going to say the hypothalamus is linked anatomically to both the anterior and posterior pituitary glands, but the hypothalamus literally controls ant pit, anterior pituitary, with hormones. What? The hypothalamus has its own hormones that it makes and it dumps them into another anatomical phenomenon called a portal system. And now that I think about this, I need another picture. So when I come back and talk to you about the pituitary gland, I'll bring a picture of the portal system, but define this. So push pause after I say it if you need more time to write it down. The portal system is a weird circulatory system that is two capillary beds in sequence. You have three of them in your whole body, three places where you're going to find a portal system and this is one of them. Capillaries, and we're going to do this with the circulatory system, capillaries are a place of exchange. They're tiny little blood vessels that allow nutrient exchange and gas exchange and garbage exchange between the cells and the tissues and the blood. And it's critical, you're done if your blood stops allowing for exchange in the capillaries. You usually have one capillary bed. The blood comes from the heart, it goes through one capillary bed, exchange happens, and then dirty blood comes out the other side of the capillary bed. In weird portal systems, you have two in sequence and it's weird because why have two? You have exchange happen in the first one and why would you go through a capillary bed? Again, you have dirty blood going through the capillary bed. You have other goals. And hypothalamus dumps hormone into one capillary bed and that hormone goes to ant pit into another capillary bed in ant pit and affects ant pit and says, hey, we need some more hormones and ant pit dumps hormones into the capillary bed which then heads out to the cells to affect the cells. So what you end up with is I'm going to draw a little star. We got a capillary bed up here, hypothalamus dumps hormone in. We got a capillary bed down here. Ant pit receives that hormone and then gets, that's the message to make more, send out hormone and affect other people. Hypothalamus controls ant pit in that way. Hypothalamus controls post pit. This is really weird. Post pit is actually like an extension of hypothalamus. It's actually neural tissue. So hypothalamus makes hormone that's stored in post pit. Did you follow that fantastic fact? So it's almost like, man, I need a bigger version of this. That's a neuron. This is the axon terminal of my neuron. The neuron cell body lives in the hypothalamus. The axon extends down and the axon terminals are in posterior pituitary. Hypothalamus makes the hormone. The axon terminals store the hormone and release it into the bloodstream. So really, post pit is just nervous system. It's just an extension of hypothalamus. The plant pit is actually endocrine tissue, which is a different thing. Okay, so you might feel like, dude, we just talked about the pituitary gland, but we're supposed to be talking about the hypothalamus, but we're going to come back and talk about the pituitary gland one more time and I'm going to bring back pictures of the capillary system.