What components make up the circulatory system?

Answer 1

The heart is basically a large muscular organ, with four hollow chambers (left and right atria and ventricles) which each take a turn at filling with blood during the course of each heart beat; there are valves between the chambers to make sure that the blood travels around the heart in one direction only, and veins and arteries leading to and from the heart. Deoxygenated blood arrives at the heart via veins called the inferior and superior vena cavae, which empty into the right atrium; from there the blood passes into the right ventricle, then is pumped out of the heart, along the pulmonary artery to the lungs, where it gets rid of carbon dioxide and picks up oxygen. Oxygenated blood travels back to the heart along the pulmonary vein, enters the left atrium, passes into the left ventricle, and is then pumped out of the heart via the aorta, to the rest of the body.