What are the mitral and tricuspid valves?

The heart has four chambers. Deoxygenated blood enters the right atrium from around the body via the superior and inferior vena cavae, and travels down through the tricuspid valve into the right ventricle.

The right ventricle pumps the deoxygenated blood to the lungs to be oxygenated, via the pulmonary artery (the only artery that carries deoxygenated blood). It returns via the pulmonary vein (the only vein that carries oxygenated blood) into the left atrium.

Oxygenated blood then enters the left ventricle (the heart's principle pumping chamber, and has particularly thick muscular walls) from the left atrium through the mitral valve. The left ventricle pumps the oxygenated blood at sufficient pressure to travel round the entire body, through the aortic valve and into the aorta.

- Qu.mstr.