1. The cardiac veins carry blood to the walls of the heart.   True   False   2. During the atrial systole, the openings of the pulmonary vein and the vena cava are _______.   open   closed   3. With reference to the heartbeat, the word 'systole' refers to a relaxation phase whereas the word 'diastole' refers to a contraction phase.   True   False   4. When the auricles of the heart contract, the ventricles relax, and vice versa.   True   False   5. During the ventricular systole, the blood enters the ventricles.   True   False   6. The right auricle of the heart receives oxygenated blood.   True   False   7. During the ventricular systole, the semilunar valves are closed.   True   False