Function of the Heart

The heart functions as a pump and is responsible for the circulation of the blood through the blood vessels. It is responsible for making blood flow through the blood vessels.

The circulation of the blood starts from the arteries, which carry blood from the heart. The aorta sends branches to the heart, head and arms, then it gives out branches to the internal organs. After that, it divides into two arteries that carry blood to the legs and feet.

The blood reaches the right side of the heart through two big veins: the superior and inferior vena cava to the right atrium. In the right atrium, most of the blood passed into the right ventricle relaxes following the previous contraction. The right atrium then contracts thus push the remaining blood to the right ventricle.

The contraction of the right ventricle pushes blood against the tricuspid valve, forcing it closed, and against the pulmonary semilunar valve, forcing it to open, thus allowing blood to enter the pulmonary trunk. The pulmonary trunk branches to form pulmonary arteries, which carry blood to each lung. In the lungs, the blood exchanges carbon dioxide for oxygen through the walls of many capillaries. Then blood flows to the left side of the heart in the pulmonary veins. After passing through the lungs, the blood enters the left atrium through the pulmonary veins. The blood passing from the left atrium to the left ventricle opens the bicuspid valve, and the contraction of the atrium completes left ventricular filling. Contraction of the left ventricle then pushes blood against the bicuspid valve, closing it, and against the aortic semilunar valve and then goes to the aorta.