cles.There are four valves, which aid in the function of keeping blood flowing in the right direction (Katz 75). Two of these are known as the atrio-ventricular valves. These two are named the mitral valve and the tricuspid valve. These valves allow the blood to flow from each atrium into the corresponding ventricle. The mitral valve connects the left atrium to the left ventricle, while the tricuspid connects the right atrium to the right ventricle. The other two valves in the heart allow blood to flow to the body from the ventricles but prevent blood from flowing backward into the ventricles from the body. These valves are known as the semilunar valves. They are named this because they are somewhat shaped like a crescent moon. The aortic semilunar valve allows blood to exit the left ventricle and enter the aorta. The aorta carries blood to the body tissues. The other valve is called the pulmonary similunar valve, which allows blood to exit the right ventricle and enter the pulmonary arteries. These arteries carry blood to the lungs to absorb oxygen, which is essential to our existence. These valves are designed to move blood in one direction only, unless damaged by injury or disease.The heart can be viewed as a precisely designed two-stage pump. The first stage is the two atria, whose function is to ensure that the ventricles are fully inflated with blood. When this occurs, the ventricles contract to force blood out into the body. Although both sides of the heart contract at the same time, they have very different functions. The right side of the heart receives oxygen free blood from the body and pumps it to the lungs. The left side receives oxygen rich blood from the lungs and pumps it to the rest of the body (Katz 95). Each red blood cell passes through the heart twice on its way to tissues. The venae cavae aids in this process by returning the deoxygenated blood to the heart. The venae cavae is also the largest v...
