This functional difference is revealed in the comparative anatomy of the two ventricles. The walls of the left ventricle are at least twice as thick as the walls of the right ventricle. This is because there is more cardiac muscle in the walls of the left ventricle, so consequently, the left ventricle is a much more powerful pump. This one-way flow of blood is enforced by the presence of 4 heart valves. They prevent backflow of blood.
Papillary muscles are small conical projections that protrude from the ventricle walls.
When blood enters an atrium, blood puts pressure on the AV valve. The papillary muscles relax and the chordae tendineae slacken, so that the AV valve flaps hang limply into the ventricular chamber. The blood flows through the open AV valve into the ventricle. When the ventricle contracts, so do the papillary muscles, causing the chordae tendineae to tighten, preventing the cusps of the valve from everting into the atrium. If the cusps were not anchored in this way, they would be pushed upward into the atria by the blood.