Blood flow to the heart

What does the right atrium (RA) do?

The right atrium (RA) receives oxygen-poor blood from all tissues, except the lungs, through the superior and inferior venae cavae. Blood flows out of the RA through the tricuspid valve into the right ventricle.

What does the right ventricle (RV) do?

The right ventricle (RV) pumps the oxygen-poor blood through the pulmonary semilunar valve and into the pulmonary artery, which carries it to the lungs.

What does the left atrium (LA) do?

The left atrium (LA) receives oxygen-rich blood from the lungs through the four pulmonary veins. The blood flows out of the LA, through the mitral valve, and into the left ventricle.

What does the left ventricle (LV) do?

The left ventricle (LV) receives oxygen-rich blood from the left atrium. Blood flows out of the LV through the aortic semilunar valve and into the aorta, which carries it to all parts of the body, except the lungs.

How does oxygen-poor blood return to the heart?

Oxygen-poor blood is returned by the venae cavae to the right atrium, and the cycle continues.