How does the heart work?

Blood rich in carbon dioxide will enter the right atrium. Blood from the upper parts of the body will drain into the superior vena cave while blood from the lower part of the body will enter through the inferior vena cave. After it enters the right atrium, it wnters the right ventricle through the tricuspid valve. The right ventricle will pump the blood rich in carbon dioxide through the lungs. The blood will then go into the pulmonary arteries to the right lung and the left lung. Gas exchange takes place. The oxygen rich blood flows back into the left atrium through pulmonary veins. Blood from the left atrium flows into the left ventricle through the bicuspid valve. Then, oxygenated blood moves up by the left ventricle though the aortic arch to the rest of the body.