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.
There are three main categories of contact lenses, based on the materials they are made of: soft contacts, rigid gas permeable (GP) contacts, and hybrid contact lenses. Soft contacts are made of pliable hydrophilic (water-loving) plastics called hydrogels.