 This is a heart. Okay, bye. Just kidding, we're almost to okay, bye, stage. Coronary circulation. Gotta feed your heart first. All of the blood vessels on the outside of the heart, these are our major veins and arteries of the coronary system. We have coronary arteries and we have coronary veins. And we also have a whole lot of other guys, like crazy lot of other guys. And we could totally learn all the anatomy of the very, very important blood vessels that are feeding the heart. What happens if those blood vessels fail to do their job? That's like if they get clogged with McDonald's or smoking, then heart tissue, cardiac muscle tissue that is downstream of that blood vessel will die. And that's what a heart attack is. A blood vessel got clogged and the tissue that that blood vessel was supplying dies. And if enough of your heart muscle dies, well, you die too, because your heart is really important to pumping all your blood all around your body. So take care of yourself. Exercise, don't eat horrible food all the time, just sometimes, every now and then. And if you're exercising and doing other healthy things, stop smoking, then you are putting yourself in an excellent position to have a heart that feeds it, so it is fed properly. If your heart is fed properly, then it's happy and it's able to do its job. Okay, the anatomy that we need to know. We already know that we have these sulcuses that we can't identify on the external surface of the heart. And what I'm telling you is the extent of our treatment of coronary circulation is going to be, oh, look, there's a bunch of coronary arteries and veins on the outside of the heart. Knowing that, dude, those things are feeding your heart tissue, it's a phenomenal external brain question. What happens if your coronary circulation gets clogged because you forgot to stop smoking? Just do it today. Stop smoking so then you won't forget. All those guys have to dump into the heart. The used up blood has to dump into the heart and the fresh blood has to come from the heart. So where does that happen? Well, you have a structure called a coronary sinus and this is a little hole found in the right ventricle. That's the right atrium. So this is the coronary sinus. Coronary sinus is where blood from the heart drains. And then this has been fantastically amazing. Somewhere we have to get blood out and guess who gets it first? Your heart, ugh, settle down, your heart gets it first. Those two dots are two little openings in the ascending aorta. As soon as we get out of the left ventricle, blood falls in, falls into those vessels and the coronary arteries. So you can actually see the opening of the coronary arteries in the ascending aorta. So those are the structures that we'll hold ourselves accountable to those. Then we'll be like, ugh, cardiac, coronary arteries and veins. And then holy capillary bed, feeding our heart. Thank you very much for continuing onward and then dumping back in the coronary sinus. The last thing we get to talk about is where your heart sounds come from.