Many people do, but the heart is actually located almost in the center of the ... During an average lifetime, the human heart will beat more than 2.5 billion times. Give a tennis ball a good ...

Day and night, the muscles of your heart contract and relax to pump blood throughout your body. In the Step Thru below, see the complicated path the blood takes as it moves in and out of the heart.

There are notable differences between men and women in their susceptibility to many human diseases, including cardiovascular ...