<s>[INST] What is stroke? [/INST] Stroke (also known as cerebrovascular disease) occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts. When that happens, part of the brain cannot get the blood and oxygen it needs, so it starts to die.

The extent and location of the brain cell damage determines the severity of the stroke, which can range from minimal to catastrophic. Because different areas of the brain control different functions, the specific effects of a particular stroke depend on which area of the brain is injured. A small stroke in a critical area of the brain can be permanently disabling.

Because brain cells do not regenerate, damage to the nerve cells is permanent. Millions of brain cells die each minute a stroke is untreated. Ruptured blood vessels cause hemorrhagic or bleeding strokes. Source: MALAYSIA STROKE COUNCIL . Link: https://www.strokecouncil.org/stroke-faq/. Field: Neurology. Disease: Stroke </s>