WEBVTT - How do strokes work?

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<v Speaker 1>Welcome to Brainstuff from how Stuff Works dot com where

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<v Speaker 1>smart Happens. Hi Am Marshall Brain with today's question, how

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<v Speaker 1>do strokes work? Like strokes that happened inside of people's

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<v Speaker 1>brains Over the weekend, a video made the rounds on YouTube.

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<v Speaker 1>The video shows a newscaster named Serene Branson giving a

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<v Speaker 1>report outside the Grammy Awards. Her first few words are okay,

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<v Speaker 1>but then what follows is undecipherable. It appears that she's

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<v Speaker 1>forgotten how to speak and can only link unrelated sounds together.

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<v Speaker 1>According to early reports, she was quickly rushed to the hospital.

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<v Speaker 1>Later reports disputed the early reports, and who knows what

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<v Speaker 1>really happened. But when those early reports came out, the

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<v Speaker 1>speculation was that she had suffered from a stroke. In

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<v Speaker 1>a stroke, something goes wrong with the supply to the brain.

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<v Speaker 1>In Branson's case, it appeared that the blood supply to

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<v Speaker 1>her speech center was suddenly interrupted. Everyone has heard of

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<v Speaker 1>a heart attack because heart attacks are the number one

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<v Speaker 1>killer in America according to the c d C, and

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<v Speaker 1>most people understand the cause of heart attacks. On the

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<v Speaker 1>outside of the heart, there are blood vessels that supply

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<v Speaker 1>oxygen and nutrients to the hearts muscle cells. If one

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<v Speaker 1>of those blood vessels gets clogged, either with plaque or

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<v Speaker 1>with a blood clot, part of the heart muscle runs

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<v Speaker 1>out of oxygen and starts dying. A stroke is the

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<v Speaker 1>same kind of thing that happens in the brain, cutting

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<v Speaker 1>off oxygen to an area of the brain and causing

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<v Speaker 1>brain cells to start dying. Strokes are currently the number

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<v Speaker 1>three cause of death in the United States. Strokes are

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<v Speaker 1>categorized by the way in which the blood supply is interrupted.

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<v Speaker 1>In the most common type of stroke, something blocks in artery.

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<v Speaker 1>The two things that can blow an artery in the

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<v Speaker 1>brain are the same two things that can block an

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<v Speaker 1>artery in the heart, either plaque or a blood clot.

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<v Speaker 1>Plaque is a fatty substance that builds up on the

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<v Speaker 1>inside of arteries, slowly filling them and shrinking the amount

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<v Speaker 1>of blood that can flow. If enough plaque builds up,

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<v Speaker 1>it cuts off blood flow completely and causes a stroke.

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<v Speaker 1>This is the most common way to have a stroke.

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<v Speaker 1>Blood clots are less likely than plaque, but they have

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<v Speaker 1>exactly the same effect. One advantage of a stroke caused

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<v Speaker 1>by a blood clot is that clots can sometimes be

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<v Speaker 1>dissolved with clot busting drugs. If dissolved quickly enough, the

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<v Speaker 1>brain can sometimes recover. The other type of stroke is

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<v Speaker 1>a hemorrhagic stroke, and here there's a rupture instead of

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<v Speaker 1>a blockage. One of the blood vessels inside the brain

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<v Speaker 1>breaks and starts bleeding. This can not only cut off

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<v Speaker 1>the blood supply, but may also cause pressure on parts

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<v Speaker 1>of the brain from the blood that escapes. The rupture

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<v Speaker 1>can come from an aneurysm, a thin part of a

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<v Speaker 1>larger blood vessel that pops like a balloon, or a rupture,

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<v Speaker 1>and a small blood vessel often triggered because blood pressure

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<v Speaker 1>is too high. Once a stroke occurs, there are a

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<v Speaker 1>number of telltale signs that may appear. A sharp, sudden

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<v Speaker 1>headache that comes out of nowhere is one of the

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<v Speaker 1>classic signs. Slurred speech, as in the case of Serene Branson,

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<v Speaker 1>is another. A sudden inability to understand or respond to

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<v Speaker 1>spoken commands usually indicates a stroke as well. If a

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<v Speaker 1>limb suddenly goes numb or goes limp or it looks

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<v Speaker 1>like the muscles on one side of the face have

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<v Speaker 1>stopped working, that would be another classic sign of a stroke.

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<v Speaker 1>Strange sudden vision problems would be another. The place where

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<v Speaker 1>the stroke occurs controls the symptoms. For example, if the

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<v Speaker 1>stroke occurs near the part of the brain that controls

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<v Speaker 1>the right arm, then the right arm will go limp.

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<v Speaker 1>There are something like seven hundred thousand strokes in the

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<v Speaker 1>United States every year. They are fairly common events, especially

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<v Speaker 1>in older adults. If you're visiting with a friend who

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<v Speaker 1>suddenly manifests strange symptoms like those described above, time is

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<v Speaker 1>of the essence. The quicker a stroke is treated, the

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<v Speaker 1>better the chances of recovery. Call nine one one immediately

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<v Speaker 1>and keep the person having the stroke calm until help arrives.

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