評論
打印
I wanna figure out how blood gets from my heart, which I'm going to draw here, all the way to my toe,
這集我們要看血液怎么從心臟流向腳趾
and I'm going to draw my foot over here and show you which toe I'm talking about.
心臟在左邊，腳趾畫在右邊，這樣來表示我們討論涉及的腳趾
Let's say this toe right here.
假設腳趾在這里
Now, to start the journey,
好，血液要流動的話
it's gonna have to go out of the left ventricle into the largest artery of the body.
從左心室流出，流入身體中最大的動脈
This is going to be the aorta, and the aorta is very, very wide across,
也就是主動脈，主動脈是非常大的一條動脈
and that's why I say it's a large artery.
實際上，是最大的一條動脈
And, from the aorta, I'm actually not drawing all the branches of the aorta,
從主動脈開始，它的分支我們不一一標明
but from the aorta, it's going to go down into my belly,
從主動脈來到腹部
and it's going to branch towards my left leg and my right leg.
然后產生左右腿的分支
So, let's say we follow just the left leg,
假設我們看左腿這邊
so this artery over here on the top, it's gonna get a little bit smaller,
那么上邊這個動脈就要小一點了
and maybe I would call this a medium-sized artery by this point.
這條動脈是中型大小
Ah, this is actually now getting down towards my ankle.
然后來到了腳踝
Let's say we've gone quite a distance down to my ankle,
假設到腳踝之前走了相當長的一段距離
and then, you know there are, of course, little branches,
當然，中間血管可能有不少分支
and let's just follow the branch that goes towards my foot, which is this top one.
我們就看腳趾部分的血管，也就是上邊這里
Let's say this one goes towards my foot,
假設這是腳趾處的血管
and this is going to be now an even smaller artery.
這個動脈要更小一點
Let's call it small artery. Small artery.
稱作小動脈
From there, we're actually going to get into what we call arterioles.
然后就來到微動脈了
So it's going to get even tinier, right? It's going to branch.
微動脈是非常非常小的動脈分支
Now, these are very, very tiny branches coming off of my small artery,
從小動脈中分出來
and let's follow this one right here, and this one is my arteriole. Arteriole.
看這里，這就是微動脈。我標一下
So, these are all the different branches I have to go through,
這些是不同的分支
and finally, I'm going to get into tiny little branches,
后來到非常小的血管分支
I'm going to have to draw them very, very skinny just to convince you that we're getting smaller and smaller.
我畫的細一點，這樣大家就知道血管是越來越細了
Let me draw three of them.
我畫三條吧
Nah, let's draw four, just for fun. Ah, four of them,
畫四條吧
and this is actually gonna now get towards my little toe cells,
這里就到腳趾細胞了
so let me draw some toe cells in here to convince you that I actually have gotten there.
在這里畫一些腳趾細胞，這里就是腳趾了
Let's say one, two over here, and maybe one over here, and these are my toe cells. Toe cells.
假設這有一個細胞，這有兩個，一個。這些都是腳趾處的細胞
And after the toe cells have kind of taken out whatever they need.
假設現在腳趾細胞已經得到了需要的養分
Maybe they need glucose, or maybe they need some oxygen.
比方說葡萄糖，或者氧氣
Whatever they have taken out,
不管腳趾細胞吸收了什么
they are also gonna put in their wastes,
同時還要排出細胞廢物
so they have, of course, some carbon dioxide waste that we need to drag back.
比方說二氧化碳，這樣血管要把廢物運回去
