Final answer:
The two upper chambers of the heart are the atria, which serve as the receiving chambers for incoming blood before it is pumped into the ventricles.
Step-by-step explanation:
The atria are known as the receiving chambers of the heart because they receive blood entering the heart. The right atrium takes in blood from the upper and lower parts of the body via the superior vena cava and inferior vena cava, while the left atrium receives oxygenated blood from the lungs through the pulmonary veins. After receiving blood, the atria contract to push the blood into the ventricles, which are the lower chambers of the heart.
The ventricles then function as the main discharging chambers, pumping blood either to the lungs or throughout the body. The septa are the walls that separate the left and right sides of the heart, the bundle of His is a collection of heart muscle cells specialized for electrical conduction that transmit the electrical impulses from the AV node to the point of the apex of the fascicular branches.