What is the primary function of the atria in the heart?

The primary function of the atria in the heart is to receive blood from the body and the lungs. The heart has four chambers: two atria and two ventricles. The atria are located at the upper part of the heart and serve as the receiving chambers. The right atrium accepts deoxygenated blood returning from the body through the superior and inferior vena cavae, while the left atrium receives oxygenated blood from the lungs via the pulmonary veins.

This receiving function is crucial for maintaining the flow of blood through the heart. Once the atria fill with blood, they contract and push the blood into the ventricles, which are responsible for pumping blood out of the heart into the lungs and the rest of the body. Therefore, recognizing the atria's role in the circulation process is essential for understanding how the heart operates as a whole.