Blood enters the heart into the right atrium. Next the blood flows into the tricuspid valve, then into the right ventricle. The valves in the heart keep the blood flowing in the right direction. Next the blood goes up higher in the heart into the pulmonary valve. Then when the blood leaves the heart and goes to the lungs. Once it reaches the lungs (which are so close to the heart) the blood fills up with oxygen. Then it comes through the pulmonary vein, into the left atrium. Next it comes down into the mitral valve and last it comes to the left ventricle.
Of the many muscles in the human body, the heart is the most important because of its hard job: Your heart pumps blood around your body. Your blood provides your whole body with the health and nutrients that your body needs to be strong and healthy. You may not have known that your heart actually takes tiny rests between each beat; that's why your heart sounds something like boom, boom rest, boom, boom rest. Your heart has two pumps: one on the left and one on the right. Here's what the job of the right side is: once the right side of your heart gets non-oxygenated blood coming from the body, it sends the blood to the lungs. The left side does something very different from the right: the left side gets blood coming from the lungs, and then pumps this oxygenated blood out into our bodies. Then this cycle repeats!
FUN FACTS ABOUT THE HEART!
Did you know that a man's heart is heavier than a woman's?
A woman's heart beats faster than a man's
The blue whale has the largest heart of all animals! Their hearts can weigh over 1,500lbs (680kg)!