What do we call the lower chambers of the human heart?

The lower chambers of the human heart are called ventricles. The right and left ventricles receive blood from the atria above them and pump it out of the heart.

The right ventricle sends oxygen-poor blood through the pulmonary artery to the lungs. The left ventricle pumps oxygen-rich blood through the aorta to the rest of the body. Because it must generate much higher pressure, the left ventricle has a substantially thicker muscular wall than the right.

A common mix-up is confusing ventricles with atria. The atria are the two upper chambers, while the ventricles are the two lower chambers. Valves between these chambers help keep blood moving in one direction, and the septum separates the right and left sides.

The word “ventricle” comes from a Latin term meaning a small cavity or belly-like chamber. Humans have two ventricles, working together in the heart’s double-circulation system.