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.
What happens during Systole. Heart muscles contract, creating pressure to open the pulmonary and aortic valves. Blood from R ventricle is pushed into the lungs to exchange O2 and CO2. Blood from the L ventricle is pushed thru the aorta to be distributed throughout the body.