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1、TED题：How high altitude affects your body作者:Andrew Lovering海拔如何影响你的身体If someone teleported from sea level to the top of Mt.Everest,things would go bad fast.At an altitude of 8,848 meters,barometric pressure is approximately 33%of what it is at sea level.This means theres significantly less oxygen in
2、the air,and our teleported individual would likely suffocate in minutes.However,for people that make this same journey over the course of a month,its possible to survive at the peak for hours.So what can happen to our bodies in just one month that allows us to endure this incredible altitude?个如果从海平
3、瞬移到珠穆朗玛峰顶上，其体情况会迅速恶化。在 8848 的海拔度上，压只有海平度的三分之，这意味着空中的氧极度稀少，这个可怜的 在分钟内就会窒息。但是，那些花个攀登到顶的 却能够在顶上存活好个时。所以，在这短短的个当中 我们的体究竟发了什么，让我们能够忍受 这得不可思议的海拔？Lets imagine youre one of the 5.8 billion people living less than 500 meters above sea level.When you take a breath at this altitude,your lungs fill up with air
4、composed of numerous gases and compounds.Most important among these are oxygen molecules,which bind to the hemoglobin in your red blood cells.Blood then circulates throughout your body,bringing essential oxygen to all your cells.But as altitude increases,the air starts to get thinner.假设你是住在 海平 500 以
5、内的 那 58 亿中的个。在这个海拔度深吸，由多种体和化合物组成的空 就会充满你的肺，其中最重要的就是氧分，氧分与红细胞中的红蛋结合，这样来，当液在体内循环，关重要的氧 就会抵达所有细胞。但当海拔升，空也随之变得稀薄。teleportv.灵运输approximatelyadv.近似的oxygenn.氧suffocatev.窒息死incredibleadj.不可信的oxygen molecules氧分hemoglobinn.红素thinneradj.稀薄的The relative amounts of each compound remain the same well into the upp
6、er atmosphere,but overall,there is less oxygen for our bodies to absorb.And if you ascend to altitudes above 2,500 meters,the resulting oxygen deprivation can cause a form of altitude sickness known as AMS,often causing headaches,fatigue and nausea.空中每种化合物的相对含量 并不会随着海拔升改变。但总的来说，供体吸收的氧分越来越少。当你爬升到 250
7、0 以上的海拔时，随之来的缺氧 会造成种海拔疾病，即“AMS”（急性症），通常表现为头疼、疲乏、恶。Fortunately,AMS only happens when we ascend too fast,because our bodies have numerous ways of adapting to high altitudes.Within minutes or even seconds of reaching altitudes of 1,500 meters,carotid chemoreceptors in your neck sense your bloods low ox
8、ygen pressure.This triggers a response that increases the rate and depth of your breathing to counteract the lack of oxygen.Your heart rate also increases and your heart contracts more tightly to pump additional blood with each beat,quickly moving oxygenated blood around your body.幸运的是，急性症 只会在海拔上升过快
9、时发，因为体针对海拔 有数的应对机制。如果在分钟甚秒钟内 到达 1500 以上的海拔，脖的颈动脉化学感受器 就会察觉到液氧压过低，触发理反应，使呼吸更快更，从弥补氧的缺乏。同时率也会加快，脏会更加地收缩，在每次跳动时带动更多的液，让充了氧的液 在体更快速地运转。All these changes happen relatively fast,and if you were to keep ascending,your heart rate and breathing would speed up accordingly.But if you stayed at this altitude fo
10、r several weeks,you could reap the benefits of some longer-term adaptations.这些变化的发相对较快，且如果你还在继续爬升，你的跳和呼吸都会相应地加快。但如果你在这个海拔 停留上个星期，你可能会因为长期适应 获得些好处。atmospheren.；氛altitude sickness海拔疾病nausean.恶反胃oxygenated blood含氧longer-term adaptation期适应Within the first few days above 1,500 meters,the volume of plasma
11、 in your blood decreases,which increases the concentration of hemoglobin.Over the next two weeks,your hemoglobin levels will continue to rise,allowing your blood to carry even more oxygen per milliliter.Paired with your high heart rate,this new hemoglobin-rich blood efficiently distributes oxygen th
12、roughout your body.So much so that the volume of blood being pumped with each heartbeat can return to normal levels.Over this same time,your breathing also increases even further in a process called ventilatory acclimatization.在 1500 以上停留的最开始天，体液内浆的含量会减少，引起红蛋浓度的增加。接下来的两个星期 红蛋平会持续增长，使得每毫升液 能够运输更多的氧，再
13、加上率，这种新的红蛋液 效地将氧运送到体各处，从使每次跳带动的液 回到正常平。同时，你的呼吸也会继续加快，这种过程被称为“通习服”。After this several weeks of extended acclimatization,your body has made enough significant changes to climb even higher.However,youll still have to spend additional time acclimating along the way,often climbing back down to recover be
14、fore ascending even higher.Because the summit of Everest isnt just high,its the highest place on Earth.And at altitudes above 3,500 meters,our bodies are under incredible stress.Arteries and veins in the brain dilate to speed up blood flow,But our smallest blood vessels,called capillaries,remain the
15、 same size.This increased pressure can cause blood vessels to leak,and fluid to build up in the brain.这种适应过程持续个星期之后，你的体就做好够的准备 能够继续向上爬了。但是，你在攀爬的过程中 还需要花额外的时间适应环境。在继续向上爬之前 们常常暂时下，进恢复。因为珠穆朗玛峰不是座，它还是世界上最的。在 3500 以上的海拔 你将承受巨的压，脑的动脉和静脉都会膨胀 以加快液流速。但我们最的管，也就是细管，仍然保持原状。增加的压会使这些管破裂，还会导致液体在脑内积聚。hemoglobinn.红素
16、heartbeatn.跳ventilatory acclimatization通习服acclimatizationn.环境适应性capillaryn.细管A similar issue can occur in the lungs,where low oxygen causes blood vessels to constrict,leading to more leaking vessels and fluid buildup.These two conditions known as HACE and HAPE,respectively are incredibly rare,but ca
17、n be life-threatening if not dealt with quickly.Some Tibetans and South Americans with family histories of living at high altitude have genetic advantages that can prevent minor altitude sickness,but even they arent immune to these severe conditions.肺部也会受到类似的威胁，肺部管会在低氧环境下收缩 进破裂，使更多液体积聚。这两种情况分别被称为 HA
18、CE 和 HAPE，它们常罕见，但如果不及时处理 可能会危及命。些中国西藏和南美地区的，其祖先活在海拔地区，所以本就能抵抗 些轻型的海拔症状。但即使是这些，也可能遭遇严重状况。Yet despite these risks,climbers over the last century have proved people can go higher than scientists ever thought possible.Pushing past their bodys limitations,these climbers have redefined what humanity can adapt to.虽然风险巨，但在过去的个世纪，登者们已经证明，类能科学家预测的爬得更，这些登者不断挑战体极限，重新定义了类对环境的适应能。respectivelyadv.各的；分别的limitationn.限制