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.
Â§ events just before and during diastole: Â§ during systole â A-V valves are closed Ã  atria filled with blood Â§ beginning of diastole â ventricular pressure decreases below that of the atria Ã  A-V valves open Â§ higher pressure in the atria pushes blood into the ventricles during diastole Â§ period of rapid filling of the ventricles occurs during the ...