you are mistaken...the ventricular walls are thicker than the auricular walls.. The left ventricle is further thicker than the right ventricle. This is because the left ventricle has to transport blood to all the parts of the body and has to travel a long distance hence requires it to be transported at great pressure. As a result the wall is thicker. The auricles only have to pump blood into the ventricles underneath them and therefore don't require alot of pressure hence are not thick. The right ventricle however pumps the deoxygenated blood into the lungs and has to travel a relatively short distance since the lungs are close to the heart hence not alot of pressure is required either. All this explains why the Ventricular walls are generally thicker than the auricular walls.
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