How many times does blood travel through the heart?

ANSWER:It actually goes through more than that, but I believe you are asking why it goes to the heart twice before it gets sent to the rest of the body. The reason is the heart has no oxygen production capabilities. It therefore receives the unoxygenated blood from the body in the Superior vena cava and into the right atrium, from there it goes to the right ventricle where it is sent to the lungs to be oxgenated through the pulmonary artery. Oxygen is picked up by the blood cells in the lungs and returns back to the heart through the pulmonary vein into the left atrium. This is the second time it enters into the heart. From the left atrium it flows into the left ventricle and then exits into the aorta to the oxygenate the rest of the body.