The Journey of Blood Through the Heart

This is the left anterior descending artery or the anterior interventricular artery. Blood enters into this right atrium from both the inferior vena cava and the superior vena cava. Once the blood enters into this right atrium, it passes through a right atrioventricular valve on its way into the right ventricle, at which point the blood then passes through this pulmonary semilunar valve, which we can't really see here, and enters into the pulmonary trunk.

The pulmonary trunk soon divides into a left pulmonary artery and a right pulmonary artery, which passes underneath the arch of the aorta. The pulmonary arteries then go out to the lungs. So if we follow this blue color, this blue color continues out and we can see it doing many branches to go into the left lung.

And on this side, following the blue, we go out into the right lung. Once the blood has been oxygenated, it is returned through what are called the pulmonary veins and the pulmonary veins. We will see these in red. So here are some of the left pulmonary veins and here are some of the right pulmonary veins.

And that blood then enters into this chamber, which is the left atrium. After passing into the left atrium, blood then passes down through this left atrioventricular valve.

And we can see it in this cutout here a little bit better where we can actually see the valve leaflets and the chordae tendineae. This is again, the left atrioventricular valve, also known as the mitral valve.

Once blood has passed through that valve, it is now into the left ventricle. And in the left ventricle we can see very nicely this formation. These are the trabeculae carne. At that point, the blood makes a turn and passes up through the aortic semilunar valve to enter into the ascending aorta, which then leads us to the aortic arch and then the descending aorta, which then goes down through the into the abdomen as the abdominal aorta.

Branches coming off of the arch of the aorta include this. Right brachiocephalic artery, a left common carotid artery and a left subclavian artery.