The Heart and Major Vessels
When you gain a pound of fat, your body creates seven miles of blood vessels.
Key Facts In This Video
The back of the heart is known as its "base". (1:26)
Veins returning from the lungs into the left side of the heart are the only veins that carry oxygenated blood. (3:37)
There are four valves leading to or from the heart. (5:01)