Anatomy of the Mammalian Heart

The heart consists of Atriums and Ventricles, 4 in total. The heart is also split into to sides, the left and right side (your perspective).

The point of your heart is to pump blood around, and the main reason for blood to exist, is to bring oxygen to your cells. The blood gets it's oxygen from the lungs. Veins coloured red contains oxygen rich blood, the blue ones contain the oxygen poor blood (sometimes you can come across purple colour, this is used for both oxygen rich and poor blood). The blood flow is as following:

1. Right atrium

2. Right ventricle

3. Pulmonary artery (artery to the lungs)

4. Pulmonary vein (vein from the lungs)

5. Left atrium

6. Left ventricle

7. Aorta

Suppose you're a red blood cell heading to your nose, starting at your lungs:

So, now we know the basics. Let's expand with some veins and arteries! The two main veins in your body are the:

1. Inferior Vena Cava
2. Superior Vena Cava

Both of them end in the right atrium, the Inferior Vena Cava comes from the bottom, and the Superior Vena Cava comes from the top. To supply your heart with oxygen, there are two main Arteries; The right coronary artery, and the left coronary artery. Of course, there's also a coronary vein.

The last thing to know about the heart, are the valves. A valve makes sure that blood can't go back. There are four valves in the heart:

1. Tricuspid Valve

2. Pulmonary Valve

3. Aortic Valve

4. Mitral Valve