Illustration copyright 2000 by Nucleus Communications, Inc. All rights reserved. http://www.nucleusinc.com

A stroke is a sudden disruption in blood flow to the brain caused by a blockage or bleeding of a blood vessel. Areas of the brain that are affected by the blockage or bleeding can become damaged within minutes. The effects of a stroke may be mild or severe and temporary or permanent. The effects depend on which brain cells are damaged, how much of the brain is involved, and how quickly the blood supply is restored to the area.