And all ion channels are selective for a single type of ion, and we can think about how that selectivity takes place, and that's where this idea of atomic radius is going to become very important.

所有的离子通道都是仅对某一种离子具有选择性的，而我们可以来想一想这种选择性是如何发生的，这也就是原子半径这个概念将会变得，非常重要的地方。

麻省理工公开课 - 化学原理课程节选

Listen the English channels even if they have subtitles.

听英文频道的广播。就算是有字幕的也要听听。

英语学习就要这样 - SpeakingMax英语口语达人

And actually, a question that might come up, I just explained, the sodium channel, you might say, well, how do potassium channels work then, because I can understand how you can filter something big out, but how do you filter out something small.

实际上，可能大家会问一个问题，我刚解释过，钠离子通道，你可以说，好吧，那么钾离子通道该如何起作用呢，因为我可以理解你是如何把大东西过滤掉的，但是你如何把小东西过滤掉呢？

麻省理工公开课 - 化学原理课程节选

Now, these are special channels in that they only allow certain molecules to pass through.

这种特殊的通道,只能允许特定的分子通过

耶鲁公开课 - 生物医学工程探索课程节选

So this is one of the local channels here around Boston.

是波士顿一家地方台。

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We can already use that in terms of single ions to think about a really complex biological issue, which is to talk about ion channels.

我们已经能够仅仅凭借这个关于单个离子的原理,来讨论一个非常复杂的生物问题了，我们要讨论的就是离子通道。

麻省理工公开课 - 化学原理课程节选

What all of these channels have is what's called a selectivity filter, so this filter filters out the type of ion that's going to be allowed through.

这些离子通道都有的一部分,就是所谓的选择性过滤器，这个过滤器,会滤过允许穿过的离子。

麻省理工公开课 - 化学原理课程节选

When an action potential is initiated these ion channels go from their closed state to their open state, when they open sodium can now pass through.

当动作电位形成时,离子通道,从关闭状态转到打开状态,当通道打开时,钠离子就可以通过

耶鲁公开课 - 生物医学工程探索课程节选

So, that is just a quick example for some of you, you might be very familiar with ion channels, others might not know what these are, so I'll just tell you quite briefly that ion channels are these very massive transmembrane proteins.

这对你们中的某些人来说仅仅是个小例子，有些人可能已经非常熟悉离子通道这个概念了，但有些人可能还不清楚，那么就让我来简单地介绍一下离子通道,就是这些巨大的跨膜蛋白。

麻省理工公开课 - 化学原理课程节选

many of these ion channels have this size exclusion pore, it's a very important part of them.

很多离子通道也都有这样的具有尺寸排斥性的小孔，这是它们非常重要的组成部分。

麻省理工公开课 - 化学原理课程节选

And when we talk about any type of ion channel, there are just tons of different kinds of ion channels, and you can characterize them in a few different ways.

而当我们讨论任何一种离子通道时，离子通道有非常多种，你可以用几种不同的方法来描述它们。

麻省理工公开课 - 化学原理课程节选

So the influx of ions from the outside of the cell to the inside of And you can think of ion channels as being gated, by gated it means the gate can be closed and no ions are going through, as in this case here.

下面以离子从细胞外部流入内部,你可以把离子通道想象成是有闸门的，也就是说闸门可以关上,这时没有离子能通过，就像这种情况。

麻省理工公开课 - 化学原理课程节选

All cell membranes have these channels within them, and under their resting conditions sodium is moving from outside to inside, potassium's moving from inside to outside.

所有细胞膜上都有这种通道结构,在静息状态下,钠从细胞外流向细胞内,钾从细胞内流向细胞外

耶鲁公开课 - 生物医学工程探索课程节选

Now, remember we talked about these last time, voltage-gated channels are channels that would allow the passage of sodium, in this case, but they can exist in two states, a closed state and an open state.

还记得我们上节课讨论过的吧,电压门控通道是,一种可以容许钠离子通过的通道,在这一例子中 电压门控通道有两种状态,关闭状态和开放状态

耶鲁公开课 - 生物医学工程探索课程节选

The cells that take an electrical signal, which is coming down your nerve and convert it into a muscle contraction work this way, so 'neuro' nerve, muscle junctions act based on ligand-gated ion channels.

依靠相同的工作原理,细胞将来自于神经的,电信号传递到细胞收缩肌中,所以神经和肌肉关节运动,都基于配体门控离子通道

耶鲁公开课 - 生物医学工程探索课程节选

Now, it's more complicated than that because it's not just sodium channels that are involved, there are potassium channels also, and the interplay between sodium channels opening and potassium channels opening, this is described in some detail in your book.

现在 事情更复杂了,因为这一过程不仅关系着钠离子通道,也关系着钾离子通道,以及钠离子通道和钾离子通道之间开关,的相互作用,书中有详细解释

耶鲁公开课 - 生物医学工程探索课程节选