The lower heart chambers are called ventricles.
During diastole the ventricles are filled with blood emptying to them from the atria.
The right ventricle is filled from the right atrium, while blood flows through the Tricuspid valve.
The left ventricle is filled from the left atrium, while blood flows through the Mitral valve.
During the systole the ventricles pump the blood contained in them into the large vessels.
The right ventricle empties to the Pulmonary artery, from which blood is transferred to the lungs.
The left ventricle empties to the Aorta.