What is the primary function of the heart's atria?

The primary function of the heart's atria is to receive blood. The atria are the upper chambers of the heart and serve as storage areas for blood as it returns from the body and lungs. The right atrium receives deoxygenated blood from the body through the superior and inferior vena cavae, while the left atrium receives oxygenated blood coming from the lungs via the pulmonary veins.

By accommodating incoming blood, the atria play a crucial role in the heart's overall function, ensuring that the ventricles (the heart's lower chambers) are appropriately filled with blood before they contract to pump blood either to the lungs or the rest of the body. This notch in the function between receiving and pumping positions the atria as essential for optimal cardiac rhythm and efficiency.