A stroke or cerebrovascular accident (CVA) occurs when the blood supply to a part of the brain is suddenly interrupted by occlusion (an ischemic stroke) or by hemorrhage (a hemorrhagic stroke). The former, ischemia, is a reduction of blood flow due to occlusion (an obstruction). The latter, hemorrhagic stroke, occurs when a blood vessel in the brain bursts, spilling blood into the spaces surrounding the brain cells or when a cerebral aneurysm ruptures. Stroke is literally a "brain attack",
caused when the vital supply of blood and oxygen is cut off to part of the brain. If a portion of the brain loses its supply of nutrient-rich blood and oxygen, the bodily functions controlled by that part of the brain (vision, speech, walking, etc.) are impaired. Like a heart attack, every minute counts in getting a stroke victim emergency medical treatment so that brain damage and possible future disability will be minimized.
