HUMAN HEART

 The human heart is a muscular organ located in the thoracic cavity, behind the sternum and between the lungs.

It has four chambers: the right atrium and ventricle, and the left atrium and ventricle. The right atrium receives deoxygenated blood from the body and pumps it into the right ventricle, which then pumps it to the lungs for oxygenation. The left atrium receives oxygenated blood from the lungs and pumps it into the left ventricle, which then pumps it to the rest of the body.

The heart also has four valves: the tricuspid valve, the pulmonary valve, the mitral valve and the aortic valve, which help regulate blood flow and prevent backflow.

The heart is surrounded by the pericardium, a sac that contains a small amount of fluid to lubricate and protect the heart. The heart is also supplied by coronary artery.