来自《耶鲁大学开放课程：生物医学工程探索 第8集 第8集》

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  so the inside of the cell is a little bit more negative than the outside.
  所以细胞内侧跟外侧比起来电势要低一些
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  Now, what happens during an action potential is that
  在动作电位产生时
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  that membrane potential changes very rapidly
  膜电位迅速改变
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  and it changes from being negative to being more positive.
  从较负的电位向更正的电位改变
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  That change happens because something gets triggered in the membrane,
  变化的原因是膜上某些东西被触发了
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  and what gets triggered is a voltage gated sodium channel,
  被触发的是钠离子电压门控通道
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  which is shown here.
  展示在这儿了
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  Now, remember we talked about these last time,
  还记得我们上节课讨论过的吧
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  voltage-gated channels are channels
  电压门控通道是
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  that would allow the passage of sodium,
  一种可以容许钠离子通过的通道
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  in this case, but they can exist in two states,
  在这一例子中 电压门控通道有两种状态
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  a closed state and an open state.
  关闭状态和开放状态