WEBVTT - BrainStuff Classics: Why Do We Itch?

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<v Speaker 1>Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,

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<v Speaker 1>I'm Lauren vocal Bam, and I've got another brain Stuff

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<v Speaker 1>classic episode for you today from our former host, Christian Sager.

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<v Speaker 1>The topic why do we Itch? Hey everybody, I'm Christian

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<v Speaker 1>Sager and this is the brain Stuff where I tell

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<v Speaker 1>you about itching. Why do we itch? Why does it

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<v Speaker 1>feel so good to scratch an itch? Well? To answer this,

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<v Speaker 1>we must first turn to one of the body's most unappreciated,

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<v Speaker 1>hardworking organs, the skin. So let's start with your skin,

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<v Speaker 1>the original clothing, your birthday suit. Skin is pretty cool stuff.

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<v Speaker 1>It is your body's largest organ. If you were to

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<v Speaker 1>stretch out the skin of the average adult, you know,

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<v Speaker 1>like if you wanted to make some cool book bindings

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<v Speaker 1>or masks or sheets or whatever, you stretch that out,

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<v Speaker 1>that would cover twenty two square air feet and weigh

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<v Speaker 1>eight pounds. That's about enough to cover the twin bed

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<v Speaker 1>in a creepy Serial Killers apartment. But while it's still

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<v Speaker 1>attached to your body, skin protects you from germs signals.

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<v Speaker 1>The immune system regulates body temperature and allows us to

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<v Speaker 1>experience the crucial sense known as touch, one type of

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<v Speaker 1>nerve ending in particular is responsible for the sensation of itching. Now,

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<v Speaker 1>as it turns out, and itch is just the street

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<v Speaker 1>name for something called paritis. Yet it's difficult to say.

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<v Speaker 1>It is the irritation of skin cells or associated nerve

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<v Speaker 1>cells caused by some external stimuli, like say tickling. Itching

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<v Speaker 1>is a built in defense mechanism that alerts your body

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<v Speaker 1>to the potential of being harmed. Think of that feeling

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<v Speaker 1>you get when an insect crawls along your skin. That's

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<v Speaker 1>your body saying watch out, that bug is out for

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<v Speaker 1>your blood. Now, this itching sensation comes from receptors. Yeah,

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<v Speaker 1>remember the whole paritis thing. That's just as difficult to say,

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<v Speaker 1>But these are specialized nerve endings in your skin. Let's

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<v Speaker 1>stick with this insect example. When the bug lands on

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<v Speaker 1>your skin, it may not bother you at first, but

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<v Speaker 1>soon it will begin to rub back and forth across

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<v Speaker 1>your skin as it walks along looking for the best

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<v Speaker 1>place to bite you. Once the bug scratches your skin,

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<v Speaker 1>surface layer receptors in the dermis of the skin will

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<v Speaker 1>become irritated. In a split second, these receptors send a

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<v Speaker 1>signal through fibers in the skin to your spinal cord

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<v Speaker 1>and then up to the cerebral cortex in your brain.

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<v Speaker 1>The same fibers that send itching signals are also used

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<v Speaker 1>to send pain signals to the brain, which once led

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<v Speaker 1>some scientists to believe that itching was a form of

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<v Speaker 1>light pain. That notion has since been dispelled by research

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<v Speaker 1>which showed that pain and itching illicit opposite responses. Pain

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<v Speaker 1>causes us to withdraw, and itching causes us to scratch.

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<v Speaker 1>As soon as we feel an itch, our first natural

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<v Speaker 1>response is to scratch the spot of the itch with

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<v Speaker 1>our fingernails. The reason for this response is simple, we

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<v Speaker 1>want to remove the irritant as soon as possible. Once

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<v Speaker 1>you've scratched the area of irritation, you are likely to

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<v Speaker 1>feel some relief. When your brain realizes that you've scratched

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<v Speaker 1>away the irritant, The signal being sent to your brain

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<v Speaker 1>that you have an itch is interrupted and therefore no

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<v Speaker 1>longer recognized. Even if you don't remove the irritant, scratching

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<v Speaker 1>will at least cause pain and divert your attention away

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<v Speaker 1>from the itching. The irritant that caused the itching is

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<v Speaker 1>very small, maybe only a few microns in length, so

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<v Speaker 1>it only disturbs a few nerve endings When you use

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<v Speaker 1>your finger nail to scratch the spot where the irritant is,

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<v Speaker 1>you not only remove the irritant, but you irritate a

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<v Speaker 1>lot more nerve endings than the irritant. In many cases,

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<v Speaker 1>an itching sensation can be related to various ailments or diseases,

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<v Speaker 1>from dry skin or poison ivy to more serious life

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<v Speaker 1>threatening internal issues. So if you have continual chronic paritis,

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<v Speaker 1>visit your local medical professional. They should be able to

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<v Speaker 1>help you find a solution, which is great because we

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<v Speaker 1>all know there are a few things worse than an

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<v Speaker 1>itch you can't scratch. Today's episode was written by Ben

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<v Speaker 1>Bolan and produced by Tyler Clang. Check out our online

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<v Speaker 1>shop at t public dot com slash Brainstuff. Every purchase

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<v Speaker 1>supports us directly, and of course, for more on this

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<v Speaker 1>and lots of other topics that will get unto your

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<v Speaker 1>skin in a good way, visit our home planet, how

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<v Speaker 1>stuff works dot com.