inferior vena cava - a large vein (a blood vessel carrying blood to the heart) that carries oxygen-poor blood to the right atrium from the lower half of the body.

left atrium - the left upper chamber of the heart. It receives oxygen-rich blood from the lungs via the pulmonary vein.

left ventricle - the left lower chamber of the heart. It pumps the blood through the aortic valve into the aorta.

mitral valve - the valve between the left atrium and the left ventricle. It prevents the back-flow of blood from the ventricle to the atrium.

pulmonary artery - the blood vessel that carries oxygen-poor blood from the right ventricle of the heart to the lungs.

pulmonary valve - the flaps between the right ventricle and the pulmonary artery. When the ventricle contracts, the valve opens, causing blood to rush into the pulmonary artery. When the ventricle relaxes, the valves close, preventing the back-flow of blood from the pulmonary artery to the right atrium.

pulmonary vein - the blood vessel that carries oxygen-rich blood from the lungs to the left atrium of the heart.

right atrium - the right upper chamber of the heart. It receives oxygen-poor blood from the body through the inferior vena cava and the superior vena cava.

right ventricle - the right lower chamber of the heart. It pumps the blood into the pulmonary artery.

septum - the muscular wall that separates the left and right sides of the heart.

superior vena cava - a large vein that carries oxygen-poor blood to the right atrium from the upper parts of the body.

tricuspid valve - the flaps between the right atrium and the right ventricle. It is composed of three leaf-like parts and prevents the back-flow of blood from the ventricle to the atrium.