but there's now millions of these of vessels all over your body.

但在全身有上百万这样的血管
The blood is not flowing at a large flow rate through a big vessel,

血液在大血管中的流速并不快
it's flowing at a much smaller flow rate through many,

在很多血管中它的流速更慢
many vessels but the total has to add up to the total that goes in.

但所有的流量的总和与入量相一致
Well, you know the rest of the story;

好的接下来的事情你们都请楚了
the capillaries merge after they leave the tissue area.

离开组织的毛细血管会融合
They merge into small veins;

它们融合成小静脉
veins are collecting tubules for de-oxygenated blood.

静脉收集血氧含量较低的静脉血
Now, this is blood that has transported all of its nutrients

这些血液中所有的养分都传输到
into the tissue that it serves

它服务的组织中去
so it doesn't have a lot of oxygen anymore.

静脉血中不再含有丰富的氧气
It has a lot of waste products now,

而是带有较多的废物