The ventricular wall is thicker than the atrium based on the physiological function of the heart. The atria mainly supply blood to the ventricles, accounting for about 25% of the blood supply to the whole heart, so the blood supply is smaller, the pressure of afterload is smaller, and the atrial wall becomes thinner. The left ventricle, on the other hand, supplies blood mainly to the whole body, and for the whole-body blood supply, the afterload itself is greater and requires more force to distribute blood throughout the body, so the walls of the left ventricle are thickest. The right ventricle, on the other hand, mainly supplies blood to the lungs, which transport blood to the left ventricle, so the wall of the right ventricle is thicker than the wall of the atria, but thinner than the wall of the left ventricle, and the ratio of the thickness of the right ventricle wall to the left ventricle wall is generally about 1/3.