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.
1 Systolic pressure denotes the maximum pressure along the blood vessels when the heart is contracting, whereas diastolic pressure indicates the minimum pressure along the blood vessels when the heart is relaxed. 2  There are four chambers of the heart: right and left atrium and right and left ventricles.