- Right atrium
- Left atrium
Human heart has four chambers : the two atria (right and left) and the two ventricle (right and left).
This is a diagram of heart with the direction of blood flow (we can see from the diagram the RA and LA receive blood) :
Among these chambers the two atria receive blood from outside of heart and the two ventricles propel blood from the heart to tissues. The right atrium receives blood from the superior and inferior vena-cava. And the left atrium receives blood from the lungs through pulmonary veins. So, these two are called the receiving chambers of the heart.