煎蛋小学堂:英语百科(视频+中英字幕) 第14课:当大脑#34;嗑#34;了咖啡
<p><span word="With">With</span> <span word="its">its</span> <span word="stimulating">stimulating</span> <span word="effects">effects</span>,<span word="its">its</span> <span word="easy">easy</span> <span word="to">to</span> <span word="undersand">undersand</span>.<span word="why">why</span> <span word="coffee">coffee</span> <span word="is">is</span> <span word="the">the</span> <span word="second">second</span> <span word="most">most</span> <span word="traded">traded</span> <span word="commodity">commodity</span> <span word="on">on</span> <span word="Earth">Earth</span> <span word="after">after</span> <span word="oil">oil</span>.<span word="For">For</span> <span word="many">many</span>,<span word="it">it</span> <span word="keeps">keeps</span> <span word="us">us</span> <span word="awake">awake</span> <span word="and">and</span> <span word="moving">moving</span> <span word="through">through</span> <span word="our">our</span> <span word="busy">busy</span> <span word="days">days</span>.咖啡的刺激效果使我们容易理解，为何咖啡是仅次于油的世界第二大交易商品。它有助于保持清醒，帮我们挺过忙碌的日子。<span word="But">But</span> <span word="how">how</span> <span word="does">does</span> <span word="it">it</span> <span word="work">work</span>?<span word="What">What</span> <span word="exactly">exactly</span> <span word="does">does</span> <span word="coffee">coffee</span> <span word="do">do</span> <span word="to">to</span> <span word="your">your</span> <span word="brain">brain</span>?<span word="Whenever">Whenever</span> <span word="youre">youre</span> <span word="awake">awake</span>,<span word="a">a</span> <span word="chemical">chemical</span> <span word="called">called</span> <span word="adenosine">adenosine</span> <span word="slowly">slowly</span> <span word="accumulates">accumulates</span> <span word="in">in</span> <span word="your">your</span> <span word="brain">brain</span>.<span word="And">And</span> <span word="this">this</span> <span word="adenosine">adenosine</span> <span word="binds">binds</span> <span word="to">to</span> <span word="receptors">receptors</span> <span word="which">which</span> <span word="slow">slow</span> <span word="down">down</span> <span word="brain">brain</span> <span word="activity">activity</span>-<span word="ultimately">ultimately</span>,<span word="the">the</span> <span word="more">more</span> <span word="adenosine">adenosine</span> <span word="there">there</span> <span word="is">is</span>,<span word="the">the</span> <span word="more">more</span> <span word="tired">tired</span> <span word="your">your</span> <span word="brain">brain</span> <span word="feels">feels</span>.<span word="Which">Which</span> <span word="makes">makes</span> <span word="sense">sense</span>,<span word="as">as</span> <span word="the">the</span> <span word="longer">longer</span> <span word="youre">youre</span> <span word="awake">awake</span>,<span word="the">the</span> <span word="more">more</span> <span word="fatigued">fatigued</span> <span word="you">you</span> <span word="become">become</span>.不过 它是怎么做到的？咖啡对大脑做了什么？当你清醒时，腺甘酸会在大脑内部逐渐积聚。腺甘酸会与减缓脑部活动的受体结合，最终，腺甘酸越多，你的大脑越累。这也有它的道理 清醒的时间越长 你也会越疲惫。<span word="Conversely">Conversely</span>,<span word="while">while</span> <span word="you">you</span> <span word="sleep">sleep</span>,<span word="the">the</span> <span word="concentration">concentration</span> <span word="of">of</span> <span word="adenosine">adenosine</span> <span word="declines">declines</span>,<span word="gradually">gradually</span> <span word="promoting">promoting</span> <span word="wakefulness">wakefulness</span>.<span word="But">But</span> <span word="it">it</span> <span word="turns">turns</span> <span word="out">out</span> <span word="that">that</span> <span word="the">the</span> <span word="caffeine">caffeine</span> <span word="in">in</span> <span word="your">your</span> <span word="coffee">coffee</span> <span word="is">is</span> <span word="incredibly">incredibly</span> <span word="similar">similar</span> <span word="to">to</span> <span word="adenosine">adenosine</span> <span word="in">in</span> <span word="structure">structure</span>.<span word="The">The</span> <span word="caffeine">caffeine</span> <span word="works">works</span> <span word="its">its</span> <span word="way">way</span> <span word="through">through</span> <span word="your">your</span> <span word="blookstream">blookstream</span> <span word="and">and</span> <span word="into">into</span> <span word="the">the</span> <span word="brain">brain</span>.<span word="where">where</span> <span word="it">it</span> <span word="starts">starts</span> <span word="to">to</span> <span word="compete">compete</span> <span word="and">and</span> <span word="binds">binds</span> <span word="with">with</span> <span word="adenosine">adenosine</span> <span word="receptors">receptors</span>.相反，当你睡眠时，腺甘酸的浓度下降，逐渐使你清醒。不过，咖啡中的咖啡因在结构上和腺甘酸很相似。咖啡因随着血液流动，进入大脑，它在此参与竞争 与腺甘酸受体结合。<span word="But">But</span> <span word="because">because</span> <span word="its">its</span> <span word="not">not</span> <span word="adenosine">adenosine</span>,<span word="thesleepiness">thesleepiness</span> <span word="effect">effect</span> <span word="isnt">isnt</span> <span word="felt">felt</span>.<span word="Adenosine">Adenosine</span> <span word="can">can</span> <span word="no">no</span> <span word="longer">longer</span> <span word="bind">bind</span>,<span word="meaning">meaning</span> <span word="its">its</span> <span word="calming">calming</span> <span word="properties">properties</span> <span word="are">are</span> <span word="diminished">diminished</span>.<span word="Which">Which</span> <span word="is">is</span> <span word="great">great</span> <span word="for">for</span> <span word="you">you</span> <span word="when">when</span> <span word="youre">youre</span> <span word="feeling">feeling</span> <span word="tired">tired</span>!<span word="However">However</span>,<span word="with">with</span> <span word="long">long</span> <span word="term">term</span> <span word="use">use</span> <span word="of">of</span> <span word="caffeine">caffeine</span>,<span word="your">your</span> <span word="brain">brain</span> <span word="responds">responds</span> <span word="by">by</span> <span word="creating">creating</span> <span word="more">more</span> <span word="adenosine">adenosine</span> <span word="receptors">receptors</span>-<span word="which">which</span> <span word="means">means</span> <span word="more">more</span> <span word="caffeine">caffeine</span> <span word="is">is</span> <span word="required">required</span> <span word="to">to</span> <span word="elicit">elicit</span> <span word="the">the</span> <span word="same">same</span> <span word="response">response</span>.由于它本非腺甘酸，因此人不会有倦意。腺甘酸不再被结合，其镇定作用就会减弱。当你感觉疲惫时，这正合你意！但是 长期使用咖啡以后，你的大脑会因而产生更多的腺甘酸受体.<span word="It">It</span> <span word="also">also</span> <span word="means">means</span> <span word="that">that</span> <span word="when">when</span> <span word="you">you</span> <span word="try">try</span> <span word="to">to</span> <span word="quit">quit</span> <span word="drinking">drinking</span> <span word="coffee">coffee</span> <span word="or">or</span> <span word="miss">miss</span> <span word="your">your</span> <span word="daily">daily</span> <span word="intake">intake</span>.<span word="you">you</span> <span word="might">might</span> <span word="experience">experience</span> <span word="some">some</span> <span word="with">with</span> <span word="drawal">drawal</span> <span word="symptoms">symptoms</span> <span word="and">and</span> <span word="feel">feel</span> <span word="more">more</span> <span word="tired">tired</span> <span word="than">than</span> <span word="you">you</span> <span word="would">would</span> <span word="have">have</span> <span word="before">before</span> <span word="you">you</span> <span word="ever">ever</span> <span word="drank">drank</span> <span word="coffee">coffee</span>!<span word="But">But</span> <span word="the">the</span> <span word="caffeine">caffeine</span> <span word="doesnt">doesnt</span> <span word="stop">stop</span> <span word="there">there</span>!<span word="It">It</span> <span word="also">also</span> <span word="stimulates">stimulates</span> <span word="the">the</span> <span word="production">production</span> <span word="of">of</span> <span word="adrenaline">adrenaline</span>-<span word="you">you</span> <span word="know">know</span>,<span word="the">the</span> <span word="Fight">Fight</span> <span word="or">or</span> <span word="Flight">Flight</span> <span word="hormone">hormone</span>?<span word="This">This</span> <span word="increases">increases</span> <span word="your">your</span> <span word="heart">heart</span> <span word="rate">rate</span>,<span word="gets">gets</span> <span word="your">your</span> <span word="blood">blood</span> <span word="pumping">pumping</span> <span word="and">and</span> <span word="even">even</span> <span word="opens">opens</span> <span word="up">up</span> <span word="your">your</span> <span word="airways">airways</span>.这也说明，当你想戒除咖啡或忘记喝时，就可能会经历某些断瘾症状，感觉比未开始喝咖啡前疲倦的多，不过，咖啡因的作用不止于此！它也会促进肾上腺素分泌，对，就是“或打或逃”的荷尔蒙？它可导致心跳加速，血流加快，甚至使导气管扩张。<span word="Furthermore">Furthermore</span>,<span word="it">it</span> <span word="affects">affects</span> <span word="Dopamine">Dopamine</span> <span word="levels">levels</span> <span word="by">by</span> <span word="preventing">preventing</span> <span word="its">its</span> <span word="reabsorption">reabsorption</span> <span word="in">in</span> <span word="the">the</span> <span word="brain">brain</span>.<span word="which">which</span> <span word="makes">makes</span> <span word="you">you</span> <span word="feel">feel</span> <span word="happy">happy</span>!<span word="In">In</span> <span word="fact">fact</span> <span word="this">this</span> <span word="is">is</span> <span word="the">the</span> <span word="exact">exact</span> <span word="same">same</span> <span word="thing">thing</span> <span word="that">that</span> <span word="cocaine">cocaine</span> <span word="does">does</span>,<span word="just">just</span> <span word="to">to</span> <span word="a">a</span> <span word="lesser">lesser</span> <span word="degree">degree</span>,<span word="its">its</span> <span word="a">a</span> <span word="drug">drug</span>,<span word="after">after</span> <span word="all">all</span>!<span word="This">This</span> <span word="dopamine">dopamine</span> <span word="stimulation">stimulation</span> <span word="is">is</span> <span word="also">also</span> <span word="the">the</span> <span word="aspect">aspect</span> <span word="of">of</span> <span word="coffee">coffee</span> <span word="that">that</span> <span word="makes">makes</span> <span word="it">it</span> <span word="moderately">moderately</span> <span word="addictive">addictive</span>.此外，它也会通过阻止大脑重吸收多巴胺来影响其水平，使你更欢脱！其实 咖啡因也起着同样的作用，只是程度较轻。毕竟，它还是药物！多巴胺刺激也使咖啡具有一定的成瘾性。<span word="So">So</span> <span word="can">can</span> <span word="you">you</span> <span word="drink">drink</span> <span word="too">too</span> <span word="much">much</span> <span word="coffee">coffee</span>? <span word="It">It</span> <span word="turns">turns</span> <span word="out">out</span> <span word="there">there</span> <span word="is">is</span> <span word="a">a</span> <span word="lethal">lethal</span> <span word="dose">dose</span> <span word="of">of</span> <span word="caffeine">caffeine</span> <span word="which">which</span> <span word="is">is</span> <span word="somewhere">somewhere</span> <span word="around">around</span> 150<span word="mg">mg</span> <span word="of">of</span> <span word="caffeine">caffeine</span> <span word="per">per</span> <span word="kilogram">kilogram</span> <span word="of">of</span> <span word="your">your</span> <span word="body">body</span>.<span word="This">This</span> <span word="means">means</span> <span word="if">if</span> <span word="you">you</span> <span word="weigh">weigh</span> 70<span word="kg">kg</span> <span word="you">you</span> <span word="would">would</span> <span word="require">require</span> 14,000<span word="mg">mg</span> <span word="of">of</span> <span word="caffeine">caffeine</span> <span word="to">to</span> <span word="overdose">overdose</span>.<span word="Put">Put</span> <span word="into">into</span> <span word="perspective">perspective</span> <span word="an">an</span> <span word="average">average</span> <span word="cup">cup</span> <span word="of">of</span> <span word="coffee">coffee</span> <span word="contains">contains</span> <span word="roughly">roughly</span> 150<span word="mg">mg</span> <span word="of">of</span> <span word="caffeine">caffeine</span>.<span word="meaning">meaning</span> <span word="if">if</span> <span word="you">you</span> <span word="are">are</span> 70<span word="kg">kg</span>,<span word="approximately">approximately</span> 70 <span word="cups">cups</span> <span word="of">of</span> <span word="coffee">coffee</span> <span word="would">would</span> <span word="kill">kill</span> <span word="you">you</span>.<span word="However">However</span>,<span word="youd">youd</span> <span word="have">have</span> <span word="to">to</span> <span word="drink">drink</span> <span word="those">those</span> <span word="cups">cups</span> <span word="all">all</span> <span word="at">at</span> <span word="once">once</span>. <span word="making">making</span> <span word="it">it</span> <span word="effectively">effectively</span> <span word="impossible">impossible</span> <span word="to">to</span> <span word="overdose">overdose</span> <span word="on">on</span> <span word="caffeine">caffeine</span> <span word="from">from</span> <span word="coffee">coffee</span>.<span word="since">since</span> <span word="you">you</span> <span word="wouldnt">wouldnt</span> <span word="be">be</span> <span word="able">able</span> <span word="to">to</span> <span word="physically">physically</span> <span word="fit">fit</span> <span word="that">that</span> <span word="much">much</span> <span word="in">in</span> <span word="your">your</span> <span word="stomach">stomach</span>.那么，喝咖啡可能过量吗？其实，咖啡因存在致死剂量，大约为每千克体重150毫克咖啡因。也就是说 如果你体重70千克 则需要14克咖啡因才会过量。形象点说，平均每杯咖啡含量有150毫克咖啡因。若你的体重为70千克 喝下70杯咖啡会致死。但是，你得一次喝下这么多咖啡，单单喝咖啡导致咖啡因过量几乎不可能，因为你根本无法将这么多东西装进胃里。<span word="Youd">Youd</span> <span word="also">also</span> <span word="start">start</span> <span word="experiencing">experiencing</span> <span word="mania">mania</span> <span word="and">and</span> <span word="hallucinations">hallucinations</span> <span word="before">before</span> <span word="getting">getting</span> <span word="to">to</span> <span word="this">this</span> <span word="point">point</span>.<span word="Caffeine">Caffeine</span> <span word="also">also</span> <span word="has">has</span> <span word="a">a</span> <span word="halflife">halflife</span> <span word="of">of</span> <span word="around">around</span> 6 <span word="hours">hours</span>-<span word="so">so</span> <span word="if">if</span> <span word="you">you</span> <span word="drank">drank</span> <span word="a">a</span> <span word="standard">standard</span> <span word="coffee">coffee</span> <span word="with">with</span> <span word="around">around</span> 150<span word="mg">mg</span> <span word="of">of</span> <span word="caffeine">caffeine</span>,<span word="after">after</span> <span word="about">about</span> 6 <span word="hours">hours</span> <span word="there">there</span> <span word="will">will</span> <span word="only">only</span> <span word="be">be</span> 75<span word="mg">mg</span> <span word="left">left</span> <span word="in">in</span> <span word="your">your</span> <span word="system">system</span> <span word="and">and</span> <span word="youll">youll</span> <span word="be">be</span> <span word="feeling">feeling</span> <span word="half">half</span> <span word="of">of</span> <span word="he">he</span> <span word="effect">effect</span>.在过量前 你也会出现狂躁和幻觉。咖啡的半排出期约为6小时，所以若你喝下的咖啡含有150毫克咖啡因，约6小时后 你的体内只剩下75毫克咖啡因，你感受到的效果也会减半。<span word="And">And</span> 6 <span word="hours">hours</span> <span word="after">after</span> <span word="that">that</span>,<span word="youll">youll</span> <span word="have">have</span> 37.5<span word="mg">mg</span>-<span word="Leaving">Leaving</span> <span word="more">more</span> <span word="room">room</span> <span word="for">for</span> <span word="adenosine">adenosine</span> <span word="to">to</span> <span word="jump">jump</span> <span word="back">back</span> <span word="into">into</span> <span word="action">action</span>.<span word="Which">Which</span> <span word="is">is</span> <span word="why">why</span> <span word="you">you</span> <span word="may">may</span> <span word="reach">reach</span> <span word="for">for</span> <span word="another">another</span> <span word="cup">cup</span> <span word="throughout">throughout</span> <span word="the">the</span> <span word="day">day</span> <span word="to">to</span> <span word="maintain">maintain</span> <span word="that">that</span> <span word="glorious">glorious</span>,<span word="alert">alert</span> <span word="and">and</span> <span word="energetic">energetic</span> <span word="feeling">feeling</span>.再过6小时 体内就仅有37.5毫克，使得腺甘酸有机可乘。这就是为何一天内，你一杯接着一杯地喝。才能保持光彩 警觉 精力十足。<span word="So">So</span> <span word="drink">drink</span> <span word="up">up</span>!<span word="And">And</span> <span word="enjoy">enjoy</span> <span word="the">the</span> <span word="buzz">buzz</span> <span word="while">while</span> <span word="it">it</span> <span word="lasts">lasts</span>:)那么喝杯咖啡吧！在作用尚存时好好享受</p>
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