Stroke
A stroke can occur when blood flow to the brain is blocked or there is sudden bleeding in the brain. There are two types of strokes. A stroke that occurs because blood flow to the brain is blocked is called an ischemic stroke. The brain cannot get oxygen and nutrients from the blood. Without oxygen and nutrients, brain cells begin to die within minutes. A stroke that occurs because of sudden bleeding in the brain is called a hemorrhagic stroke. The leaked blood results in pressure on brain cells, damaging them.