Then, whatever is not reabsorbed, plus what's secreted,

那么任何没有被重吸收和排泌的物质
is what ends up in the urine after it flows through all the tubules.

流经所有的小管后会留在尿液中
What's different here is then instead of showing

有一点不同的是这幅图没有展示
the complex geometry of the tubules,

小管的复杂的几何结构
this just shows a tube which is going to the bladder down here.

它只展示了一个向下进入膀胱的管子
This diagram is simplified because I wanted to

这幅图被简化了因为我想
just talk about one concept and that's this glomerular filtration rate,

只讲解肾小球过滤率这一个概念
the rate at which fluid is produced in the glomeruli of all of the kidneys.

液体在肾脏中肾小球被生产的速率
The question is how would you measure this

问题是你如何来测量
glomerular filtration rate in people?

人们的肾小球过滤率
If it's an important measure of kidney function

既然它是一个衡量肾功能的重要手段
how would you measure it?

那该怎么去测量呢