Located almost in the center of the chest, the adult human heart is about the size of two fists held side-by-side.

The heart is a pump made of muscle tissue. Its pumping action is regulated by electrical impulses.

Coronary arteries supply blood to the heart muscle. There are two main coronary arteries: the right and the left.

Heart valves prevent the backward flow of blood. They act as one-way inlets of blood on one side of a ventricle and one-way outlets of blood on the other side of a ventricle.

Heart disease is one of the most serious health problems in the United States. Find out more facts and figures on this topic.