some become like arteries,

一些分化为动脉
and they start to connect to the vascular system of the mouse.

它们开始与小鼠的血管系统相连
If you wait long enough

如果你等待足够长的时间后
and you look by electron microscopy inside these gels,

再用电镜观察这些凝胶
you will find many, many blood vessels that look like this.

你就会发现很多很多像这样的血管
This is a cross-section in this Panel B below.

这是下图培养皿B的横截面
You can see the endothelial cells have formed into a capillary,

你会看到这些上皮细胞变成了毛细血管
it's a tube.

它是一个管子
Not only is it a tube

它又不仅是一个管子
but here's a mouse blood cell inside of it.

其中还有小鼠的血细胞
It's a tube that's now carrying mouse blood through it.

这种管子现在能够运输小鼠的血液
You've created new pathways for blood to flow.

你制造了一个血液流动的新通路