Like all cells, brain cells need oxygen to survive. Oxygen-rich blood, flowing through the body's circulatory system, provides vital oxygen to the brain cells. Without blood to supply oxygen, brain cells are seriously damaged or destroyed. Strokes are generally categorized as being either ischemic or hemorrhagic. This is similar to a heart attack caused by cardio-vascular blockages.
Ischemic strokes are usually the result of a blood clot that blocks the flow of blood to the brain.
A hemorrhagic stroke occurs when an intra-cranial blood vessel ruptures, reducing or disrupting the flow of blood to the brain. The sudden rupture allows blood to escape from the blood vessel and leak into the brain. There are two types of hemorrhagic stroke. The other type of hemorrhagic stroke is referred to as a subarachnoid hemorrhage. With hemorrhagic stroke, the results can vary dramatically.