Is the atrium or the ventricle bigger?

The human hear has four chambers, two Atria and tow Venticles, one left and one right of each. The Right Atrium pushes blood into the Right Ventircle which then pushed the blood around the pulmonary (lungs) circulation. Once the Blood return, oxygenated, from the lungs it enters the Left Atrium which pushes it ito the Left Ventricle which in turn pushes the blood all around the body, including right up to the top of the head. Just by looking at the distance each chamber has to push the blood is a good indicator of the size of the musclular wall of each. The vetricles are therefore much larger than the atria and the left is much larger than the right.