Answer
The left ventricle is more muscular than the right ventricle because it pumps the blood at a higher pressure. Just as any other muscle in your body... If you work one and not the other- the one you work gets bigger and the opposing won't. The left ventricle pumps blood at a higher pressure because it has a further distance to travel, blood from the left ventricle goes to all areas of the body. The right ventricle only has to pump blood to the lungs which is a much shorter distance, therefore less pressure is required.
