Which two chambers are known as the "receiving" chambers of the heart?

The right and left atria are referred to as the "receiving" chambers of the heart because they are responsible for collecting blood that returns to the heart from the body and the lungs. The right atrium receives deoxygenated blood from the body via the superior and inferior vena cavae, while the left atrium collects oxygenated blood from the lungs through the pulmonary veins.

This distinction is important because, after the atria fill with blood, they contract to push blood into the ventricles, which are the "pumping" chambers of the heart. Understanding the function and role of the atria is crucial for comprehending cardiac physiology and the overall circulation of blood within the body.