Blood carries needed oxygen and nutrients to the nerve cells in the brain, so when the blood supply is cut off, the cells begin to die.
Nerve cells are the control centers that send messages to the muscles.
When cells die, muscles stop functioning too. These spells warn of a possible major stroke and should never be ignored, even when they go away on their own. The most common kind of stroke results from a blood clot that blocks an artery carrying blood to the brain. Sometimes fat deposits have made the artery's passageway narrow and uneven, causing the blood to slow down and clot around the deposits. Other times a blood clot breaks off from a larger clot in the neck or heart and is carried in the bloodstream until it reaches a narrow blood vessel in the brain where it gets stuck.