Cardiovascular System The two main roles of cardiovascular system are to maintain oxygen supply to all parts of the body and to help get rid of carbon dioxide and to transport materials such as glucose to the cells. The heart is made up of specialised cardiac muscle and is known as a double pump because each slide of the heart works separately. The right side of the heart works separately. The right side pumps blood from the heart to the lungs and the left side pumps blood from the lungs via the heart to the rest of the body. The heart has also a special valve that makes sure the blood always pumps in the right direction. The muscle of the heart is specialised because it needs to be strong enough to beat every day for the whole of a human lifespan. The heart has four chambers. These are the right atrium, right ventricle, left atrium and left ventricle. The muscular wall of the left ventricle is much thicker than the right because it has to pump blood around the whole