What does the liver do? - Emma Bryce

3,071,949 views ・ 2014-11-25

TED-Ed


Please double-click on the English subtitles below to play the video.

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There's a factory inside you that weighs about 1.4 kilograms
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and runs for 24 hours a day.
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This is your liver, the heaviest organ in your body,
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and one of the most crucial.
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This industrious structure simultaneously acts as a storehouse,
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a manufacturing hub,
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and a processing plant.
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And each of these functions involve so many important subtasks
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that without the liver, our bodies would simply stop working.
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One of the liver's main functions is to filter the body's blood,
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which it receives in regular shipments from two sources:
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the hepatic artery delivers blood from the heart,
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while the hepatic portal vein brings it from the intestine.
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This double delivery fills the liver with nutrients,
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that it then sorts, processes and stores
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with the help of thousands of tiny internal processing plants,
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known as lobules.
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Both blood flows also deliver the oxygen that the liver needs to function.
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The blood that is received from the intestine
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contains carbohydrates, fats,
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and vitamins and other nutrients dissolved in it
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from the food you've consumed.
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These must be processed in different ways.
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In the case of carbohydrates,
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the liver breaks them down and converts them into sugars
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for the body to use as energy when the filtered blood is sent back out.
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Sometimes the body has leftovers of nutrients
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that it doesn't immediately require.
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When that happens, the liver holds some back,
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and stacks them in its storage facility.
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This facility works like a pantry
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for future cases when the body might be in need of nutrients.
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But the blood flowing into the liver isn't always full of good things.
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It also contains toxins and byproducts that the body can't use.
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And the liver monitors these strictly.
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When it spots a useless or toxic substance,
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it either converts it into a product that can't hurt the body
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or isolates it and whisks it away,
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channeling it through the kidneys and intestine to be excreted.
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Of course, we wouldn't consider the liver a factory
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if it didn't also manufacture things.
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This organ makes everything from various blood plasma proteins
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that transport fatty acids and help form blood clots,
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to the cholesterol that helps the body create hormones.
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It also makes vitamin D and substances that help digestion.
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But one of its most vital products is bile.
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Like an eco-friendly treatment plant,
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the liver uses cells called hepatocytes
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to convert toxic waste products into this bitter greenish liquid.
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As it's produced, bile is funneled into a small container below the liver,
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called the gallbladder,
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before being trickled into the intestine
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to help break down fats, destroy microbes, and neutralize extra stomach acid.
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Bile also helps carry other toxins and byproducts from the liver
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out of the body.
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So as you can see,
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the liver is an extremely efficient industrial site,
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performing multiple tasks that support each other.
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But such a complex system needs to be kept running smoothly
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by keeping it healthy
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and not overloading it with more toxins than it can handle.
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This is one factory we simply can't afford to shut down.
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