Day and night, the muscles of your heart contract and relax to pump blood throughout your body. When blood returns to the heart, it follows a complicated pathway. If you were in the bloodstream ...

the human heart will beat more than 2.5 billion times. Give a tennis ball a good, hard squeeze. You're using about the same amount of force your heart uses to pump blood out to the body.

It also shows how the pacemaker cells restart her heart after the surgery. This short film is from the BBC series, Inside the Human Body. The 3D footage brings the topic to life and would enhance ...

Your heart and lungs work together to pump blood throughout your body. Oxygen rich blood from ... through your lungs because of the pressure inside these vessels. As a result, the lower chamber ...