来自《耶鲁大学开放课程：生物医学工程探索 第17集 第17集》

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  if you study more renal physiology.
  如果你深入学习肾生理学的话就会学到
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  There's a reason why the fluid goes down and goes up
  液体来回折返流动的原因是
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  and it's to establish these gradients which the kidney uses to concentrate
  建立这些梯度 从而让肾脏得以浓缩尿液
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  or extract water from the urine.
  或从尿液中提取水分
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  This orange area here represents the flow going
  这里的橙色区域代表着液体
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  from the distal convoluted tubule back into the collecting duct
  从远曲小管出发流回集合管
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  and down through the collecting duct and eventually into the ureter.
  并向下通过集合管最终进入输尿管
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  This is just a more complicated diagram of
  这张图也是我所说的这些东西
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  what I've told you already and it's--
  只不过更复杂一些
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  I encourage you to sort of walk through it
  我鼓励你们通看一遍
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  and look at all the parts so you have a sense for
  每个部分都落实一下
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  how the anatomy of the kidney works.
  好对肾脏的解剖及其作用加深印象