Your blood, blood vessels, and heart make up your circulatory system. Your heart pumps the blood, w...
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Your blood, blood vessels, and heart make up your circulatory system. Your heart pumps the blood, which carries oxygen and nutrients through your arteries to all the cells of your body. Your brain cells need a constant supply of oxygen and the nutrient glucose, which are delivered via your bloodstream. A stroke occurs when the blood supply to brain cells is cut off and they begin to die. In an ischemic stroke, a blood clot blocks the flow of blood to the brain. This is usually related to atherosclerosis, in which a fatty substance called plaque builds up on the inner walls of the arteries. A blood clot can form in the arteries that carry blood to the brain, or it can form in another part of the body and break off. The clot can then travel to blood vessels supplying the brain and gets stuck, blocking flow to the brain. Within a few seconds without oxygen, brain cells start to die and brain damage begins.