However, when that gate is opened, the sodium channel is now going to be incredibly selective and only let through sodium ions and no other type of ion.
但是,当闸门打开的时候,钠离子通道,将会有极高的选择性,不允许除钠离子以外的任何其它离子通过。
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?
The ones that are most important in physiology are ones that only allow ions to go through: sodium, potassium, chloride, calcium, bicarbonate.
在生理学上这种,只能允许某种离子通过的通道十分重要,这些离子包括钠离子,钾离子,氯离子,钙离子和碳酸氢根离子
So, what happens, this is another view of a sodium channel, so this is actually looking a little bit more at the protein structure.
那么,这里发生了什么,这是钠离子通道的另一张图片,在这种蛋白质结构中,它看起来更复杂一点。
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
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
So, for example, if we look at sodium channels, and sodium channels are some of the particularly prevalent ones when we're talking about neurons, if you think about the cell membrane, and this little green cartoon is me trying to show a sodium channel here, and in this case, you can see that it's closed, such that no ions are getting through.
比如,让我们来看一下钠离子通道,钠离子通道是我们会经常遇到的几个之一,在讨论神经元的时候,如果大家想想细胞膜,而这个绿色的小示意图就是我用来表示,钠离子通道的,在这种情况下,大家可以看到它是关闭的,因此没有离子可以通过。
For these purposes think about a channel, it only allows sodium to go through for example.
基于此目的,我们来讲离子通道,拿仅允许钠离子通过的通道作为例子
That change happens because something gets triggered in the membrane, and what gets triggered is a voltage gated sodium channel, which is shown here.
变化的原因是膜上某些东西被触发了,被触发的是钠离子电压门控通道,展示在这儿了
That's shown functionally here but recovery means that this sodium channel becomes closed again.
在此展示了这项功能,恢复代表着钠离子通道再次关闭
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
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