 Hello, everybody. We're here to cover day two of the cardiovascular system. In the last lecture, we talked about blood and blood vessels. Today, we get to talk about the heart. The heart is the pump of the circulatory system. And what I would like to start us with, I know this will never, you'll never believe it's true. I want to start us with a drawing, a big picture overview of the cardiovascular system with a few more anatomical details like drawn in to our picture. And so, of course, we have to start with our very anatomically correct heart because you know this is what your heart looks like. And then you know it looks like this, and then you know it looks like that, and that. Oh, that's your heart. Okay, bye-bye now. Just kidding. Let's draw in our vessels. You remember that we had a right and left side of my heart, and this was my right side, my right atrium, and this is my right ventricle, which means this is my left ventricle and my left atrium. I'm going to be a little sparse about the labels at the moment, but I just want to make sure that you remember that in this diagrammatic view, we're actually looking at the four chambers of the heart. In a second, I'm going to bring over a picture of a real heart so that you can see the anatomical distinctions that we're kind of trying to pull out here. There is, there are one-way valves found separating or found between the chambers of the heart, and the one-way valves allow blood only to go one direction. Now, I'm going to draw in a little bit of anatomical accuracy here. We have a vessel that feeds blood. What color did I make this blood? Of course, I made it deoxygenated. Deoxygenated blood from, do you remember from the previous one? From the body flows into the right atrium in the heart. I'm fleshing out some detail, so we're not just going to have a body box this time. We're going to get a little more specific when we start labeling the great vessels of the heart. Great vessels are the blood vessels that actually enter and exit the heart itself. The vessel, I'm making this also a little bit more anatomically correct. We have a vessel that leaves the right ventricle, taking the dirty blood with it, and this vessel actually sort of branches like a, like a this. Then, so where did that one go? You know, you know where it went. It went to the lungs, didn't it? Yes, and then fresh, lovely blood comes back from the lungs, and this is interesting because we actually have a couple of vessels that feed in from the lungs. And I'm just going to draw my other two, there's basically two vessels coming in from each side, each lung. The left lung sends two vessels in, and the right lung sends two vessels in of freshly oxygenated blood. And then the blood travels into the left ventricle, and from the left ventricle, we're still dealing with oxygenated blood, but in the left ventricle, we have something that kind of looks like this, and you get this arch that happens, and we will label all of these parts, but I just wanted to kind of review this yet again. And once again, I wish I had made my heart a different color. It's not the same color as my freshly oxygenated carrying vessels. Okay, so you see my anatomy. Now I'm going to bring over, well, maybe I'm going to bring over. I'm going to try to bring over an actual heart. Can I do that? No, I can do that so that you can just have a visual of how this compares to the image that we've drawn. So if you check it out, here, this is the two vessels that I drew, the big, long, tall vessel, and this is my right atrium. Here's a valve that's going into the right ventricle, just like this. Leaving the right ventricle is a vessel that almost looks like a T to big ol' artery. It's going to the lungs. Coming back from the lungs, we've got these two vessels and I can see them on both sides. I could draw my other two like they did. I kind of like that. But then we would have more red lines over here and, you know, it's crazy enough as it is. So these vessels come in and they dump into the left atrium, got there, travels through a valve and into the left ventricle and then up through this you can see a lovely arch and then the arch is actually going to travel down here. What do you notice about these vessels? Do you notice that they also have valves? And you can see, you can imagine what these valves are going to be doing and we will fill this in. We will fill in the anatomical details of this. But I wanted you to have a diagram of a more fleshed out anatomical diagram of the heart so that you can have the context when you're putting the pieces together. Now, we've got our overview. We know who we're coming from the body. Okay, never mind. We don't have our overview done yet. We're coming from the body, dirty blood. We're heading to the lungs and we're coming from the lungs and we're going to the body. And I'm just labeling the blood flow in this diagram so that you are comfortable and have that perspective. So you can draw in your arrows and do all that stuff. Before we go any further into anatomy awesomeness, we get to take a look at the cavity. We get to revisit a cavity we know and love already. It's the cavity that contains the heart and what cavity is that? It's the pericardial cavity. So we're going to talk in the next lecture about all the anatomical significances of the pericardial cavity.