Why are the ventricals called the pumping chambers?

The ventricles are called the pumping chambers of the heart because they are responsible for pumping blood out of the heart to the lungs and the rest of the body. The right ventricle pumps deoxygenated blood to the lungs for oxygenation, while the left ventricle pumps oxygenated blood to systemic circulation. Their muscular walls are thicker than those of the atria, enabling them to generate the high pressure needed for effective blood circulation.