1 00:00:00,160 --> 00:00:02,760 Speaker 1: Streaming TV shows and movies directly to your home is 2 00:00:02,759 --> 00:00:05,560 Speaker 1: a breeze with Netflix. As a Netflix member, you can 3 00:00:05,600 --> 00:00:09,040 Speaker 1: instantly watch TV and movies on your PC, Mac, mobile device, 4 00:00:09,160 --> 00:00:12,400 Speaker 1: or television. Get a free thirty day trial membership. Go 5 00:00:12,520 --> 00:00:15,200 Speaker 1: to Netflix dot com, slash stuff and sign up today. 6 00:00:15,880 --> 00:00:19,160 Speaker 1: Welcome to Brainstuff from house stuff works dot com where 7 00:00:19,200 --> 00:00:30,880 Speaker 1: smart happens. Hi Am Marshall brand with today's question, When 8 00:00:30,960 --> 00:00:34,920 Speaker 1: you have an itch, what's actually happening inside your skin? 9 00:00:36,200 --> 00:00:39,400 Speaker 1: The average human body is covered by about twenty square 10 00:00:39,479 --> 00:00:42,839 Speaker 1: feet or two square meters of skin, and if you 11 00:00:42,880 --> 00:00:45,479 Speaker 1: think about it, skin is the only organ in the 12 00:00:45,560 --> 00:00:49,680 Speaker 1: human body that's constantly exposed to potential irritation from the 13 00:00:49,720 --> 00:00:53,559 Speaker 1: outside elements. With so many things coming into contact with 14 00:00:53,640 --> 00:00:56,720 Speaker 1: your skin daily, you're bound to get an itch or two. 15 00:00:57,200 --> 00:01:00,960 Speaker 1: Serious switching can be caused by allergies, to z s, emotions, 16 00:01:01,000 --> 00:01:03,880 Speaker 1: and infections. But let's take a look at what causes 17 00:01:03,960 --> 00:01:08,639 Speaker 1: the common itches that aggravate you every day. Itching, also 18 00:01:08,800 --> 00:01:13,440 Speaker 1: known as puritis, starts with some kind of external stimuli, 19 00:01:13,760 --> 00:01:19,240 Speaker 1: including bugs, dust, clothing fibers, and hair like tickling, Itching 20 00:01:19,440 --> 00:01:22,440 Speaker 1: is a built in defense mechanism that alerts your body 21 00:01:22,440 --> 00:01:25,800 Speaker 1: to the potential of being harmed. In this case, it 22 00:01:25,880 --> 00:01:28,400 Speaker 1: might be the potential of being bit by a bug. 23 00:01:29,000 --> 00:01:32,080 Speaker 1: When the stimuli lands on your skin, it may not 24 00:01:32,240 --> 00:01:34,760 Speaker 1: bother you at first, but soon it will begin to 25 00:01:34,880 --> 00:01:38,319 Speaker 1: rub back and forth across your skin. Once the hair 26 00:01:38,600 --> 00:01:42,880 Speaker 1: or dust scratches your skin, surface layer receptors in the 27 00:01:42,920 --> 00:01:47,120 Speaker 1: dermness of the skin will become irritated. In a split second, 28 00:01:47,280 --> 00:01:50,680 Speaker 1: these receptors send a signal through fibers in the skin 29 00:01:50,760 --> 00:01:53,720 Speaker 1: to your spinal cord and then up to the cerebral 30 00:01:53,800 --> 00:01:57,800 Speaker 1: cortex in your brain. The same fibers that send itching 31 00:01:57,880 --> 00:02:01,120 Speaker 1: signals are also used to send pain signals to the brain, 32 00:02:01,640 --> 00:02:05,080 Speaker 1: which once led some scientists to believe that itching was 33 00:02:05,160 --> 00:02:08,320 Speaker 1: a form of light pain. That notion has since been 34 00:02:08,360 --> 00:02:12,320 Speaker 1: dispelled by research which showed that pain and itching elicit 35 00:02:12,440 --> 00:02:17,160 Speaker 1: opposite responses. Pain causes us to withdraw, and itching causes 36 00:02:17,240 --> 00:02:20,080 Speaker 1: us to scratch. As soon as we feel an itch, 37 00:02:20,320 --> 00:02:23,560 Speaker 1: our first natural response is to scratch the spot of 38 00:02:23,600 --> 00:02:27,040 Speaker 1: the itch with our fingernails. The reason for this response 39 00:02:27,120 --> 00:02:30,119 Speaker 1: is simple, we want to remove the irritant as soon 40 00:02:30,160 --> 00:02:34,200 Speaker 1: as possible. Once you scratch the area of irritation, you're 41 00:02:34,240 --> 00:02:37,920 Speaker 1: likely to feel some relief. When your brain realizes that 42 00:02:37,960 --> 00:02:41,200 Speaker 1: you've scratched away the irritant, the signal being sent to 43 00:02:41,240 --> 00:02:44,600 Speaker 1: your brain that you have an itch is interrupted and 44 00:02:44,639 --> 00:02:48,280 Speaker 1: therefore no longer recognized by the brain. Even if you 45 00:02:48,440 --> 00:02:52,040 Speaker 1: don't remove the irritants, scratching will at least cause pain 46 00:02:52,240 --> 00:02:55,680 Speaker 1: and divert your attention away from the itching. The irritant 47 00:02:55,760 --> 00:02:59,359 Speaker 1: that caused the itching is very small, usually maybe only 48 00:02:59,400 --> 00:03:02,200 Speaker 1: a few might runs in length, so it disturbs only 49 00:03:02,240 --> 00:03:05,440 Speaker 1: a few nerve endings. When you use your fingernail to 50 00:03:05,520 --> 00:03:08,600 Speaker 1: scratch the spot where the irritant is, you not only 51 00:03:08,680 --> 00:03:11,840 Speaker 1: remove the irritant, but you irritate a lot more nerve 52 00:03:11,960 --> 00:03:16,320 Speaker 1: endings than the irritan did. Be sure to check out 53 00:03:16,360 --> 00:03:19,560 Speaker 1: our new video podcast, Stuff from the Future. Join How 54 00:03:19,600 --> 00:03:22,120 Speaker 1: Stuff Work staff as we explore them as promising and 55 00:03:22,200 --> 00:03:26,880 Speaker 1: perplexing possibilities of tomorrow the house Stuff Works. I find 56 00:03:26,919 --> 00:03:34,239 Speaker 1: app has arrived. Download it today on iTunes. Audible dot 57 00:03:34,280 --> 00:03:37,560 Speaker 1: Com is the leading provider of downloadable digital audio books 58 00:03:37,560 --> 00:03:41,280 Speaker 1: and spoken word entertainment. Audible has over one hundred thousand 59 00:03:41,320 --> 00:03:44,120 Speaker 1: titles to choose from to be downloaded to your iPod 60 00:03:44,240 --> 00:03:47,640 Speaker 1: or MP three player. Go to audible podcast dot com 61 00:03:47,680 --> 00:03:50,200 Speaker 1: slash brain stuff to get a free audio book download 62 00:03:50,240 --> 00:03:51,960 Speaker 1: of your choice when you sign up today.