Annual deaths from tornadoes, earthquakes and floods together total fewer than 200. The most deadly heat wave in recent years occurred in Chicago over a week in July 1995, when temperatures hovered around 100 degrees.
Cardiac Cycle: 1st Systole Phase. During the systole phase, the right ventricle receives impulses from the Purkinje fibers and contracts. The atrioventricular valves close and the semilunar valves open. The de-oxygenated blood is pumped into the pulmonary artery.
Noun. 1. systole-the contraction of the chambers of the heart (especially the ventricles) to drive blood into the aorta and pulmonary artery. heartbeat, beat, pulse, pulsation-the rhythmic contraction and expansion of the arteries with each beat of the heart; he could feel the beat of her heart.. systole-the contraction of the chambers of the heart (especially the ventricles) to drive blood into the aorta and pulmonary artery. heartbeat, beat, pulse, pulsation-the rhythmic contraction and expansion of the arteries with each beat of the heart; he could feel the beat of her heart.