 Okay, pulmonary circulation, easy-peasy. We've already gone crazy places. We brought dirty blood back through some flavor of vena cava into the right atrium, into the right ventricle, up the pulmonary trunk. Do you agree that that looks like a trunk that's going to branch into left and right pulmonary arteries? Let's go straight forward. So this is my pulmonary trunk. Here is my pulmonary trunk. It forms that T. And then these guys are taking blood away from the heart. So these are my right and left pulmonary arteries. So the trunk is one thing that branches into my pulmonary arteries, one for the right side, one for the left side. Who's going to bring blood back from the vein, and the lungs, pulmonary veins? And these guys are pulmonary veins, and there's four of them, two from each side of the heart, that dump blood back into the left atrium. And then now you've got all your pieces. Now we have all our great vessels. Let's take a deep breath and let's do coronary circulation really fast. In coronary circulation, we're just going to look at how we feed the heart. That's only if I can figure out how to turn off the computer.