The heart has four chambers.
Blood is pumped through the chambers, aided by four heart valves.
The valves open and close to let the blood flow in only one direction. The tricuspid valve is located between the right atrium and right ventricle. The pulmonary or pulmonic valve is between the right ventricle and the pulmonary artery. The mitral valve is between the left atrium and left ventricle. The aortic valve is between the left ventricle and the aorta.