There are many different parts of the heart. One of these parts is the atrium. There is also the aorta. The aorta is the main artery in your heart. It carries oxygen rich blood from the left side of your heart to places all over your body. You also have the ventricles. The ventricles are the lower chambers on both sides of your heart. The ventricles receive blood from the atrium, which contracts to push the blood out and into the ventricles. The ventricles supply blood to your body by pumping it out of the heart. The vena cava is a main vein in your body. It carries blood from your body to the right side of your heart!