What are the upper chambers of the heart called, which receive blood from the body and lungs?

The upper chambers of the heart are known as the atria. Each atrium plays a crucial role in the heart's function by receiving blood before it is sent to the lower chambers. The right atrium collects deoxygenated blood from the body through the superior and inferior vena cavae, while the left atrium gathers oxygenated blood from the lungs via the pulmonary veins. This organization allows for efficient filling of the ventricles, which are the lower chambers responsible for pumping blood out of the heart to the lungs and the rest of the body. Understanding the function of the atria is fundamental to comprehending overall cardiac physiology and how blood circulation works.