 Brain is an important one. We probably should make sure we've got a nice little blood supply. We're going to deal with the brain. We're going to deal with arterial circulation to the brain. We're going to get fresh, good blood there. And then I'm not going to draw the, we're going to do a little more diagrammatic approach to bringing the dirty blood back to the heart. So that's why you only see one heart here, and we're going to do this all on one heart. Think, in fact, pause and guess. Like try and speculate. I've already given you some of the big vessels that are involved in this. And so push pause and see what you can fill out just from what you already know. And now that you're back, because you always do exactly what I tell you to do. Now, because we're dealing with right and left sides of the aortic arch, we've got some asymmetry. Remember that this guy is my brachiosophallic artery. I've already drawn it out once, so you can know how to do it because I did it really well. Every single branch off of the aorta has some, off of the aortic arch has some significant role in feeding the brain. So I think it's super obvious that left common carotid would be involved in head, absolutely. But left subclavian also has a branch that heads to the brain. So we're going to make note of right subclavian as well, because there is, like I said, there's a branch that comes off of it. Now brachiosophallic artery, do you remember what the anatomical structure was that told us we are no longer in subclavian, we are now in brachiosophallic? This is our friend, the right common carotid artery. And they're headed up, clinical significance. The common carotid arteries are where you can take your neck pulse, what's that called? It's carotid pulse. And so you can actually feel the heart beating through that artery in your neck. Okay, now I'm going to show you first of all my other branch, and I'm going to make my other branch a slightly different color, even though it's still arterial blood. And I'm making it a different color just so you are excited, because you know it's always important to be excited. Okay, this guy branches off the subclavian on the right and the left side. It then travels forward, and these guys travel together up the transverse foramina in cervical vertebra. Do you remember learning about the difference like how you knew cervical vertebrae were cervical and not thoracic or lumbar, is that they had those little holes in the transverse processes. Those holes were our transverse foramina, and these arteries travel through those holes and up to the brain. These arteries are the vertebral arteries. I can see that I am going to need more room like that. The vertebral arteries, we don't get a new name when we branch off the left subclavian. The left subclavian continues on to do its thing, but now these vertebral arteries are heading up the transverse foramina in your neck, and then they join each other. They join each other at the base of your brain, so now they're actually in your skull. And I'm going to show you what this actually looks like, but they join together, the two vertebral arteries join together to form the basilar artery. The basilar artery feeds into the phenomenal and quite famous circle of Willis. And I'm sorry, we're not supposed to call it the circle of Willis anymore because that is a term that is... I don't know, they're trying to remove all the people's names from the anatomical structures and scientific terminology, but I definitely learned everything with people's names attached, and circle of Willis is one of my favorite names in anatomy. The alternative is the cerebral arterial circle. You're welcome to call it either thing. Circle of Willis is way easier for me to remember. Okay, circle of Willis is... I'm going to show you a picture of where it's located, but first of all, I want to show you that the circle of Willis is a site where all sorts of vessels come in and branch off, coming in in addition to the basilar artery, coming into the circle of Willis, who's this. Common carotid both sides feed into the circle of Willis. You can imagine the circle of Willis is like a roundy round. It's like here comes multiple different sources of blood, and then it circles around and branching off of the circle are a whole bunch of other arteries that are going to ultimately feed our brain. We're going as far as circle of Willis, knowing full well that if we wanted to name all the branches that come off of the circle of Willis, we totally could do that. I don't think so. Here's a picture of the circle of Willis. Check it out. The basilar artery passes over the ponds. Under the ponds, it touches the ponds. And you can see my vertebral arteries that combine to form the ponds, and all these other things that we totally could name, but we're not going to. You can see where the carotid artery comes and feeds into this circle. And that's the important thing. I just wanted you to see where, oh, the circle actually surrounds the pituitary gland, which is another, like, wow, that's really cool. All right. As far as circle of Willis goes, we're done. As far as arterial, like, we're going to get to the circle of Willis and then we're going to say, okay, and then blood feeds the brain through capillary beds, knowing full well that there are many other vessels that divide off or branch off of the circle of Willis and all the branches that come off of the branches and you get very detailed anatomy for the brain. Let's drain it. Here's the interesting thing. If we're going to drain the brain, first of all, don't lose sight of the fact that we had a capillary bed. We did capillary action in order to do exchange, and now we're going to have a whole bunch of venules and bigger and bigger veins that we're, like, drawing blood into. The interesting thing about veins in the brain is that they're not really veins, they're like spaces, and so they have a name called the dural venous sinuses. Dural venous sinuses. So what I'm going to show you is that our dirty blood ultimately is going to drain into these dural venous sinuses. And then what I'm also going to tell you is once again, there are, like, a bunch of those, and they all have different locations and we could totally name all of them and we won't. We're going to call, we're going to do, yeah, it's all of them together, that's cool. The dural venous sinuses ultimately drain into the jugular vein, the internal jugular vein. And what do you remember about internal jugular veins? They're draining and they flow, they join with subclavian vein. So I'm going to just draw my internal jugular vein. It joins with subclavian vein to become who? Brachiosophallic. The brachiosophallic vein and then the brachiosophallic. This would be my right brachiosophallic and, excuse me, not like that. The left brachiosophallic, how's that? The left brachiosophallic combines with the right brachiosophallic to form who? This is review. Why do I do that? That's like the second time I've done that or maybe the 9 millionth time. Superior vena keva, which is rat, her. And then we're back. Do you follow what we just did? That's kind of nice. I like it, sort of. Yeah. Okay, that was it. That's all for Brain Land. Now we're going to skip a whole bunch of thoracic structures and talk about the abdomen.