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
I've seen like harp players on the underground and then classical music to kind of...
我在地下通道见过弹竖琴的人,也见过弹奏古典乐的……
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。
It has a gate on it and that gate is in open or close state depending on whether a ligand is present or not.
在这个通道上有个门,这个门是打开还是关闭,取决于配体到来与否
If a ligand comes and interacts with a receptor, it opens up; In the presence of this ligand, if the ligand goes away, it closes.
如果配体与受体相互作用,在配体存在的情况下通道打开,如果配体脱离,通道就关闭
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
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。
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
The balance of sodium movement relative to potassium movement changes because there's this resting movement of all these molecules anyway, but that balance changes dramatically when these ion - when these gated ion channels open.
钠钾各自运动始终保持动态的平衡,因为尽管在静息状态,所有这些离子也在运动,但是平衡的剧烈变化,只发生在这些门控离子通道打开的时侯
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