Explain why in the heart the wall of the left ventricle is thicker than the wall of the right ventricle?

This is because the left ventricle pumps oxygenated blood round the entire body while the right ventricle only pumps blood to the lungs which is a much shorter distance. Because the left ventricle needs to pump the blood further it needs to generate more force during contraction in order to do this. This extra force is generated due to the additional muscle found in the left ventricle wall compared to the right ventricle wall. Additionally, the blood being pumped to the lungs from the right ventricle needs to be at a lower pressure in order to prevent damage to the many thin capilaries the blood goes through in the lungs. This helps to explain why the wall of the right ventricle is thinner.