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  • Say you're at the beach, and you get sand in your eyes.

    假設你在海灘上,沙子進了眼睛

  • How do you know the sand is there?

    你怎麼知道有沙子呢?

  • You obviously can't see it, but if you are a normal, healthy human,

    顯然你看不到,但若你是個正常、健康的人

  • you can feel it,

    你可以感覺到有沙子

  • that sensation of extreme discomfort, also known as pain.

    這種極不舒服的感覺叫做「疼痛」

  • Now pain makes you do something,

    疼痛要你採取行動

  • in this case, rinse your eyes until the sand is gone.

    此例中是要你沖洗眼睛,直到沙子消失

  • And how do you know the sand is gone? Exactly. Because there's no more pain.

    你怎麼知道沙子不見了? 沒錯,因為不痛了

  • There are people who don't feel pain.

    有人感覺不到疼痛

  • Now, that might sound cool, but it's not.

    聽起來很酷,但其實一點也不酷

  • If you can't feel pain, you could get hurt, or even hurt yourself

    如果感覺不到疼痛,你可能會受傷,甚至可能傷到自己

  • and never know it.

    卻完全不知道

  • Pain is your body's early warning system.

    疼痛是你身體的早期預警系統

  • It protects you from the world around you, and from yourself.

    可保護你不受到周圍世界或自己的傷害

  • As we grow, we install pain detectors in most areas of our body.

    隨著我們長大,疼痛感測器會安裝在身體的大多數地方

  • These detectors are specialized nerve cells

    這些感測器是特殊的神經細胞

  • called nociceptors.

    稱為「痛覺感受器」

  • that stretch from your spinal cord to your skin, your muscles, your joints,

    分布在脊髓、皮膚、肌肉、關節

  • your teeth and some of your internal organs.

    牙齒和一些內臟

  • Just like all nerve cells, they conduct electrical signals,

    就像所有的神經細胞,它們用電傳送信號

  • sending information from wherever they're located back to your brain.

    從它們所在之處,送訊號回大腦

  • But, unlike other nerve cells,

    不像其他神經細胞

  • nociceptors only fire if something happens that could cause or is causing damage.

    痛覺感受器只在可能、或正在造成傷害時才會作用

  • So, gently touch the tip of a needle.

    所以,輕摸針尖

  • You'll feel the metal, and those are your regular nerve cells.

    你可以感覺到金屬,一般神經細胞給你這種感覺

  • But you won't feel any pain.

    但你不會感到任何疼痛

  • Now, the harder you push against the needle,

    但你越用力推針尖

  • the closer you get to the nociceptor threshold.

    越接近痛覺感受器的閾值 (譯註:閾值指的是生物上產生神經脈衝的門檻。)

  • Push hard enough, and you'll cross that threshold and the nociceptors fire, telling your body to stop doing whatever you're doing.

    很用力的話,就會超過閾值,痛覺感受器啟動,告訴你的身體停止目前的行為

  • But the pain threshold isn't set in stone.

    痛覺感受器的門檻,並非一成不變

  • Certain chemicals can tune nociceptors,

    某些化學物質可以調節感受器

  • lowering their threshold for pain.

    降低痛覺的閾值

  • And when cells are damaged, they and other nearby cells

    細胞受損時,受損細胞及鄰近細胞

  • start producing these tuning chemicals like crazy,

    開始瘋狂生產這些調節化學物質

  • lowering the nociceptors' threshold to the point where just touch can cause pain.

    降低痛覺感受器的門檻,直到連觸摸都會疼痛

  • And this is where over-the-counter painkillers come in.

    這時非處方的止痛藥就可以大展身手了

  • Aspirin and ibuprofen

    阿斯匹靈和布洛芬

  • block production of one class of these tuning chemicals,

    可阻止一種調節化學物質的生產

  • called prostaglandins.

    稱為「前列腺素」

  • Let's take a look at how they do that.

    我們來探討一下原理

  • When cells are damaged, they release a chemical called arachidonic acid.

    當細胞損傷,會釋放一種化學物質 叫做「花生油酸」

  • Now, two enzymes called COX-1 and COX-2

    有兩種酵素 COX-1 和 COX-2

  • convert this arachidonic acid into prostaglandin H2,

    可將花生油酸轉換成前列腺素 H2

  • which is then converted into a bunch of other chemicals that do a bunch of things,

    再將其轉換成一系列化學物質 產生一連串效果

  • including raise your body temperature, cause inflammation

    包括升高體溫、引起發炎、

  • and lower the pain threshold.

    降低疼痛閾值

  • Now, all enzymes have an active side.

    所有的酵素有特定的活性部位

  • That's the place in the enzyme where the reaction happens.

    也就酵素反應發生的地方

  • The active sites of COX-1 and COX-2

    COX-1 和 COX-2 的活性部位

  • fit arachidonic acid very cozily.

    非常適合花生油酸

  • As you can see, there is no room to spare.

    正如你看到的,也沒有多餘的空間

  • Now, it's in this active site that aspirin and ibuprofen do their work.

    阿斯匹靈和布洛芬,就是在這個 活性部位發揮作用

  • So, they work differently -- aspirin acts like a spine from a porcupine.

    它們的工作原理不同: 阿斯匹靈像豪豬的刺

  • It enters the active site and then breaks off,

    進入活性部位,然後脫落

  • leaving half of itself in there,

    留下一半在那裡

  • totally blocking that channel and making it impossible for the arachidonic acid to fit.

    完全阻斷通道,讓花生油酸進不來

  • This permanently deactivates COX-1 and COX-2.

    永久停用 COX-1 和 COX-2

  • Ibuprofen, on the other hand,

    另一方面,布洛芬

  • enters the active site, but doesn't break apart or change the enzyme.

    進入活性部位,但不破壞或改變酵素

  • COX-1 and COX-2 are free to spit it out again,

    COX-1 和 COX-2 可把它再吐出來

  • but for the time that ibuprofen is in there,

    但布洛芬在那裡的期間

  • the enzyme can't bind arachidonic acid,

    酵素無法結合花生油酸

  • and can't do its normal chemistry.

    因此無法進行正常的化學反應

  • But how do aspirin and ibuprofen know where the pain is?

    阿斯匹靈和布洛芬 怎麼知道哪裡痛?

  • Well, they don't.

    噢,它們並不知道

  • Once the drugs are in your bloodstream,

    一旦藥物進入血液中

  • they are carried throughout your body,

    就會被帶往全身

  • and they go to painful areas just the same as normal ones.

    不但會到疼痛部位,也會到正常部位

  • So that's how aspirin and ibuprofen work.

    這就是阿斯匹靈和布洛芬的原理

  • But there are other dimensions to pain.

    還有其他種類的疼痛

  • Neuropathic pain, for example,

    例如神經性疼痛

  • is pain caused by damage to our nervous system itself;

    是神經系統本身受損所引起的疼痛

  • there doesn't need to be any sort of outside stimulus.

    不需要任何形式的外界刺激

  • And scientists are discovering that the brain controls how we respond to pain signals.

    科學家們發現,大腦控制了我們對疼痛信號的反應

  • For example, how much pain you feel can depend on

    例如,疼痛的程度取決於

  • whether you're paying attention to the pain, or even your mood.

    你對疼痛的在意程度 甚至是你的心情

  • Pain is an area of active research.

    疼痛是個活躍的研究領域

  • If we can understand it better, maybe we can help people manage it better.

    如果能更了解疼痛,或許就更能有效的處理疼痛

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B1 中級 中文 美國腔 TED-Ed 感受器 痛覺 細胞 酵素 活性

【TED-Ed】止痛藥如何發揮作用?How do pain relievers work? - George Zaidan (How do pain relievers work? - George Zaidan)

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    Ashley Chen 發佈於 2018 年 03 月 24 日
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