评论
打印
Let's talk about blood vessels
这集我们接着看血管的内容
I'm going to talk to you about the different types of blood vessels that there are
我们要考虑的就是不同的血管类型
and we're going to see if we can come up with some general patterns.
我们看不同的血管，看能不能找到什么共同的规律
So let's start with the uh
首先我们来看
let's say we take the blood vessel out of your body and we examine it under a microscope.
假设我们取出一条血管，拿到显微镜下观察
It would look something like this,
差不多就是这样的
where you have the middle: called the lumen.
最中间是内腔
And right outside of the lumen you have cells.
内腔外边是一层细胞
And these cells are going all the way around the lumen
这些细胞紧密包围血管内腔
and they're the first type of cell that any blood would interact with, right?
同时它们也是跟血液接触的第一类细胞
Because that's right immediately outside of the lumen.
因为它们是与内腔紧密接触的
And on the other side of the cells, on the back side of the cells
细胞的另一边，或者如果把内腔看成细胞的前边的话
if you think of the lumen as the front side- is a little line I'm gonna draw here
我们看细胞层的后边我们画一条线
to represent protein that sits there and acts as a scaffold,
代表这层起支架作用的蛋白质
kind of like keeping all of the cells in place.
保持细胞紧密接触内腔
So you have all of these endothelial cells.
这些是内皮细胞
And then you have that little base membrane- like a thin line of membrane- called the base membrane
然后是基膜，就是薄薄的一层膜
And that keeps everything from falling out of place.
作用是保持内部的结构不变
And the thing that's in the base membrane is mostly protein.
基膜中的物质，基本就是蛋白质
So think about things like collagen which you can find in bones and your gums.
比方说，大家想一下骨骼或者牙龈中的胶原
That same protein is actually lining all of these blood vessels that are in your body.
同样的蛋白质也存在于血管中
And together the base membrane and endothelial cells,
而基膜和内皮细胞
they make up a layer called the Tunica- write it nice and big- Intima.
统称内膜，首字母大写，
They make up a layer called the Tunica Intima.
它们构成内膜
And that's kind of the word we use because "tunica" comes from the word for coat or cloak.
大家看这个名词"Tunica Intima"，tunica意思是“表面”
And "intima" is kind of the intimate layer, the intimate coating of the vessels
intima意思是“内层”，代表血管的内层
So Tunica Intima.
这就是血管内膜
Now right outside of this is another layer- and I'm gonna draw that here in red.
在内膜的外边，我用红色画这一层
And this will be a layer of muscle.
这是一层肌肉
Imagine these little lines represent smooth muscle cells.
这代表一层平滑肌细胞
So this would be muscle and this would be the layer called tunica media, or middle.
这是肌肉细胞，这层叫做血管中膜
And the most important thing here is that there is smooth muscle in this layer.
最重要的一点就是记住，这层中有平滑肌细胞
And finally, on the very outside, you have another layer.
最后，是外层
And I'm gonna draw it as a yellow line.
我用黄线画
And this yellow line represents more protein.
黄线代表的还是蛋白质
This is another layer of protein, just like the base membrane,
这是另一层蛋白质，就像基膜那样
but different composition of proteins.
只不过蛋白质的成分不同
But again you see actually a lot of collagen, just as before, and some other proteins as well.
还是大量的胶原，同时有一些其他的蛋白质
And this is called the tunica externa, for external layer.
这层叫做血管外膜
Actually another word that they sometimes use for this is called "Adventitia."
或者还有一个术语是Adventitia
So you might see that word too.
它的意思也是外膜
And the really interesting thing about the tunica externa is that you actually, on the large vessels,
外膜有一个特点，就是对一些大血管来说
you find that they need blood to supply themselves,
它们也需要血管提供营养
so some of these large vessels have little blood vessels on them.
所以有的大血管外壁上有小血管
