full transcript

From the Ted Talk by Emma Bryce: Why do we itch?

Unscramble the Blue Letters

You're standing at the ready inside the goal when suddenly, you feel an intense itch on the back of your head. We've all experienced the annoyance of an inconvenient itch, but have you ever pondered why we itch in the first place? The average person experiences dozens of individual iecths each day. They can be triggered by all sorts of things, including allergic reactions, dyrness, and even some diseases. And then there are the mysterious ones that pop up for no reason at all, or just from talking about itching. You're scratching your head right now, aren't you? Anyhow, let's take one of the most common sources: bug bites. When a mosquito bites you, it releases a compound into your body called an anticoagulant that prevents your blood from clotting. That compound, which we're mildly agirellc to, triggers the release of histamine, a chemical that makes our claarpieils swell. This enables iesnacred bolod flow, which helpfully accelerates the body's immune response to this perceived threat. That explains the slleinwg, and it's the same reason ploeln can make your eyes puff up. Histamine also activates the nerves involved in ictihng, which is why bug bites make you scratch. But the itchy sensation itself isn't yet fully understood. In fact, much of what we do know comes from sinudytg the mcacehnis of itching in mice. Researchers have discovered that itch signals in their skin are tamrinstetd via a scluabss of the nerves that are associated with pain. These dacdeietd nerves produce a molecule called natriuretic polypetide B, which triggers a sganil that's carried up the spinal cord to the bairn, where it creates the feeling of an itch. When we scratch, the action of our fingernails on the skin causes a low level pain signal that oeirvrdes the itching sensation. It's almost like a drcoaisittn, which creates the sensation of relief. But is there actually an evolutionary purpose to the itch, or is it simply there to aonny us? The leading theory is that our skin has evolved to be acutely aware of tcuoh so that we're equipped to deal with risks from the outside world. Think about it. Our automatic scratching response would dislodge anything harmful that's potentially linrkug on our skin, like a harmful sting, a biting insect, or the tendrils of a poisonous plant. This might eaplixn why we don't feel itching inside our bodies, like in our intestines, which is safe from these external treahts, though iaingme how maddening that would be. In some people, glitches in the pathways responsible for all of this can cause excessive itching that can actually harm their health. One extreme example is a psychological condition called dslureoy parasitosis where people believe their bodies are infested with metis or fales scunirryg over and under their skin, mikang them itch incessantly. Another phenomenon called phantom itching can ocucr in patients who've had amputations. Because this injury has so severely damaged the nervous system, it confuses the body's naomrl nerve signaling and creates sensations in limbs that are no longer there. Doctors are now fnndiig ways to treat these itching anomalies. In amputees, mirrors are used to reflect the remaining limb, which the patient scratches. That creates an illusion that tricks the brain into thinking the imaginary itch has been satisfied. Oddly enough, that actually works. Researchers are also searching for the geens iovnvled in itching and developing tmaeentrts to try and block the pathway of an itch in extreme caess. If having an uacclnbasrthe itch feels like your own personal hell, Dante agreed. The Italian poet wrote about a seoctin of hell where plepoe were phseiund by being left in pits to itch for all eternity.

Open Cloze

You're standing at the ready inside the goal when suddenly, you feel an intense itch on the back of your head. We've all experienced the annoyance of an inconvenient itch, but have you ever pondered why we itch in the first place? The average person experiences dozens of individual ______ each day. They can be triggered by all sorts of things, including allergic reactions, _______, and even some diseases. And then there are the mysterious ones that pop up for no reason at all, or just from talking about itching. You're scratching your head right now, aren't you? Anyhow, let's take one of the most common sources: bug bites. When a mosquito bites you, it releases a compound into your body called an anticoagulant that prevents your blood from clotting. That compound, which we're mildly ________ to, triggers the release of histamine, a chemical that makes our ___________ swell. This enables _________ _____ flow, which helpfully accelerates the body's immune response to this perceived threat. That explains the ________, and it's the same reason ______ can make your eyes puff up. Histamine also activates the nerves involved in _______, which is why bug bites make you scratch. But the itchy sensation itself isn't yet fully understood. In fact, much of what we do know comes from ________ the _________ of itching in mice. Researchers have discovered that itch signals in their skin are ___________ via a ________ of the nerves that are associated with pain. These _________ nerves produce a molecule called natriuretic polypetide B, which triggers a ______ that's carried up the spinal cord to the _____, where it creates the feeling of an itch. When we scratch, the action of our fingernails on the skin causes a low level pain signal that _________ the itching sensation. It's almost like a ___________, which creates the sensation of relief. But is there actually an evolutionary purpose to the itch, or is it simply there to _____ us? The leading theory is that our skin has evolved to be acutely aware of _____ so that we're equipped to deal with risks from the outside world. Think about it. Our automatic scratching response would dislodge anything harmful that's potentially _______ on our skin, like a harmful sting, a biting insect, or the tendrils of a poisonous plant. This might _______ why we don't feel itching inside our bodies, like in our intestines, which is safe from these external _______, though _______ how maddening that would be. In some people, glitches in the pathways responsible for all of this can cause excessive itching that can actually harm their health. One extreme example is a psychological condition called ________ parasitosis where people believe their bodies are infested with _____ or _____ _________ over and under their skin, ______ them itch incessantly. Another phenomenon called phantom itching can _____ in patients who've had amputations. Because this injury has so severely damaged the nervous system, it confuses the body's ______ nerve signaling and creates sensations in limbs that are no longer there. Doctors are now _______ ways to treat these itching anomalies. In amputees, mirrors are used to reflect the remaining limb, which the patient scratches. That creates an illusion that tricks the brain into thinking the imaginary itch has been satisfied. Oddly enough, that actually works. Researchers are also searching for the _____ ________ in itching and developing __________ to try and block the pathway of an itch in extreme _____. If having an _____________ itch feels like your own personal hell, Dante agreed. The Italian poet wrote about a _______ of hell where ______ were ________ by being left in pits to itch for all eternity.

Solution

  1. lurking
  2. increased
  3. capillaries
  4. touch
  5. scurrying
  6. itches
  7. involved
  8. overrides
  9. allergic
  10. mechanics
  11. dedicated
  12. punished
  13. delusory
  14. imagine
  15. normal
  16. making
  17. genes
  18. dryness
  19. pollen
  20. section
  21. explain
  22. blood
  23. cases
  24. unscratchable
  25. finding
  26. people
  27. itching
  28. swelling
  29. subclass
  30. mites
  31. signal
  32. fleas
  33. transmitted
  34. threats
  35. studying
  36. annoy
  37. distraction
  38. occur
  39. treatments
  40. brain

Original Text

You're standing at the ready inside the goal when suddenly, you feel an intense itch on the back of your head. We've all experienced the annoyance of an inconvenient itch, but have you ever pondered why we itch in the first place? The average person experiences dozens of individual itches each day. They can be triggered by all sorts of things, including allergic reactions, dryness, and even some diseases. And then there are the mysterious ones that pop up for no reason at all, or just from talking about itching. You're scratching your head right now, aren't you? Anyhow, let's take one of the most common sources: bug bites. When a mosquito bites you, it releases a compound into your body called an anticoagulant that prevents your blood from clotting. That compound, which we're mildly allergic to, triggers the release of histamine, a chemical that makes our capillaries swell. This enables increased blood flow, which helpfully accelerates the body's immune response to this perceived threat. That explains the swelling, and it's the same reason pollen can make your eyes puff up. Histamine also activates the nerves involved in itching, which is why bug bites make you scratch. But the itchy sensation itself isn't yet fully understood. In fact, much of what we do know comes from studying the mechanics of itching in mice. Researchers have discovered that itch signals in their skin are transmitted via a subclass of the nerves that are associated with pain. These dedicated nerves produce a molecule called natriuretic polypetide B, which triggers a signal that's carried up the spinal cord to the brain, where it creates the feeling of an itch. When we scratch, the action of our fingernails on the skin causes a low level pain signal that overrides the itching sensation. It's almost like a distraction, which creates the sensation of relief. But is there actually an evolutionary purpose to the itch, or is it simply there to annoy us? The leading theory is that our skin has evolved to be acutely aware of touch so that we're equipped to deal with risks from the outside world. Think about it. Our automatic scratching response would dislodge anything harmful that's potentially lurking on our skin, like a harmful sting, a biting insect, or the tendrils of a poisonous plant. This might explain why we don't feel itching inside our bodies, like in our intestines, which is safe from these external threats, though imagine how maddening that would be. In some people, glitches in the pathways responsible for all of this can cause excessive itching that can actually harm their health. One extreme example is a psychological condition called delusory parasitosis where people believe their bodies are infested with mites or fleas scurrying over and under their skin, making them itch incessantly. Another phenomenon called phantom itching can occur in patients who've had amputations. Because this injury has so severely damaged the nervous system, it confuses the body's normal nerve signaling and creates sensations in limbs that are no longer there. Doctors are now finding ways to treat these itching anomalies. In amputees, mirrors are used to reflect the remaining limb, which the patient scratches. That creates an illusion that tricks the brain into thinking the imaginary itch has been satisfied. Oddly enough, that actually works. Researchers are also searching for the genes involved in itching and developing treatments to try and block the pathway of an itch in extreme cases. If having an unscratchable itch feels like your own personal hell, Dante agreed. The Italian poet wrote about a section of hell where people were punished by being left in pits to itch for all eternity.

Frequently Occurring Word Combinations

ngrams of length 2

collocation frequency
bug bites 2

Important Words

  1. accelerates
  2. action
  3. activates
  4. acutely
  5. agreed
  6. allergic
  7. amputations
  8. amputees
  9. annoy
  10. annoyance
  11. anomalies
  12. anticoagulant
  13. automatic
  14. average
  15. aware
  16. bites
  17. biting
  18. block
  19. blood
  20. bodies
  21. body
  22. brain
  23. bug
  24. called
  25. capillaries
  26. carried
  27. cases
  28. chemical
  29. clotting
  30. common
  31. compound
  32. condition
  33. confuses
  34. cord
  35. creates
  36. damaged
  37. dante
  38. day
  39. deal
  40. dedicated
  41. delusory
  42. developing
  43. discovered
  44. diseases
  45. dislodge
  46. distraction
  47. doctors
  48. dozens
  49. dryness
  50. enables
  51. equipped
  52. eternity
  53. evolutionary
  54. evolved
  55. excessive
  56. experienced
  57. experiences
  58. explain
  59. explains
  60. external
  61. extreme
  62. eyes
  63. fact
  64. feel
  65. feeling
  66. feels
  67. finding
  68. fingernails
  69. fleas
  70. flow
  71. fully
  72. genes
  73. glitches
  74. goal
  75. harm
  76. harmful
  77. head
  78. health
  79. hell
  80. helpfully
  81. histamine
  82. illusion
  83. imaginary
  84. imagine
  85. immune
  86. incessantly
  87. including
  88. inconvenient
  89. increased
  90. individual
  91. infested
  92. injury
  93. insect
  94. intense
  95. intestines
  96. involved
  97. italian
  98. itch
  99. itches
  100. itching
  101. itchy
  102. leading
  103. left
  104. level
  105. limb
  106. limbs
  107. longer
  108. lurking
  109. maddening
  110. making
  111. mechanics
  112. mice
  113. mildly
  114. mirrors
  115. mites
  116. molecule
  117. mosquito
  118. mysterious
  119. natriuretic
  120. nerve
  121. nerves
  122. nervous
  123. normal
  124. occur
  125. oddly
  126. overrides
  127. pain
  128. parasitosis
  129. pathway
  130. pathways
  131. patient
  132. patients
  133. people
  134. perceived
  135. person
  136. personal
  137. phantom
  138. phenomenon
  139. pits
  140. place
  141. plant
  142. poet
  143. poisonous
  144. pollen
  145. polypetide
  146. pondered
  147. pop
  148. potentially
  149. prevents
  150. produce
  151. psychological
  152. puff
  153. punished
  154. purpose
  155. reactions
  156. ready
  157. reason
  158. reflect
  159. release
  160. releases
  161. relief
  162. remaining
  163. researchers
  164. response
  165. responsible
  166. risks
  167. safe
  168. satisfied
  169. scratch
  170. scratches
  171. scratching
  172. scurrying
  173. searching
  174. section
  175. sensation
  176. sensations
  177. severely
  178. signal
  179. signaling
  180. signals
  181. simply
  182. skin
  183. sorts
  184. spinal
  185. standing
  186. sting
  187. studying
  188. subclass
  189. suddenly
  190. swell
  191. swelling
  192. system
  193. talking
  194. tendrils
  195. theory
  196. thinking
  197. threat
  198. threats
  199. touch
  200. transmitted
  201. treat
  202. treatments
  203. tricks
  204. triggered
  205. triggers
  206. understood
  207. unscratchable
  208. ways
  209. works
  210. world
  211. wrote