How do your kidneys work? - Emma Bryce

你的肾脏如何工作？

翻译人员: Jingyao Xue 校对人员: Jenny Yang

It's a hot day,

这是炎热的一天

and you've just downed several glasses of water,

你刚一口气 喝几杯水

one after the other.

一杯接一杯

Behind the sudden urge that follows are two bean-shaped organs

跟随突然强烈欲望背后， 是两个豆状的器官

that work as fine-tuned internal sensors.

在体内工作, 作为微调内部传感器

They balance the amount of fluid in your body,

他们平衡流体 数量在体内

detect waste in your blood,

检测废物在血液中

and know when to release the vitamins, minerals,

并知道什么情况下 释放维生素，矿物质

and hormones you need to stay alive.

和激素，你需要这些 来维持生命

Say hello to your kidneys.

向你肾脏问好

The main role of these organs is to dispose of waste products

肾脏主要的作用 是清除废物

and to turn them into urine.

并把它们变成尿液

The body's eight liters of blood pass through the kidneys

人体的8升血液 要通过肾脏

between 20 and 25 times each day,

每天20和25次之间

meaning that, together, these organs filter about 180 liters every 24 hours.

这意味双肾脏透析约 180升血液每24小时

The ingredients in your blood are constantly changing

你血液的成分 是不断变化的

as you ingest food and drink,

当你摄取食物和饮料时

which explains why the kidneys need to be on permanent duty.

这解释了为什么 肾脏必须永久工作

Blood enters each kidney through arteries that branch and branch,

血液进入每个肾脏通过 分支又分叉的动脉

until they form tiny vessels that entwine with special internal modules,

直到他们形成微小血管， 紧紧交织一起的特殊内部组件

called nephrons.

称为肾元

In each kidney,

在每一个肾脏

1 million of these nephrons form a powerful array of filters and sensors

这一百万个肾元形成 强有力过滤和感应器队列

that carefully sift through the blood.

通过血液仔细筛选

This is where we see just how refined

这是我们看到的 情况，只是如何净化

and accurate this internal sensing system is.

而准确定义这个 内部传感系统是

To filter the blood, each nephron uses two powerful pieces of equipment:

过滤血液，每个肾元单位 使用两件强大装备

a blob-like structure called a glomerulus, and a long, stringy, straw-like tubule.

肾小球（斑点状结构）和 和细长微小管

The glomerulus works like a sieve, allowing only certain ingredients,

肾小球工作如筛子， 只允许某些成分

such as vitamins and minerals, to pass into the tubule.

如维生素和矿物质， 经过微小管

Then, this vessel's job is to detect

该小管任务是查明

whether any of those ingredients are needed in the body.

是否体内需要 任何这些成分

If so, they're reabsorbed in amounts that the body needs,

如果身体需要，他们再 吸收，身体所需数量

so they can circulate in the blood again.

这样他们可以 在血液中再循环

But the blood doesn't only carry useful ingredients.

但血液中不仅 携带有用的成分

It contains waste products, too.

它也包含了废物

And the nephrons have to figure out what to do with them.

肾元要搞清楚 如何处理它们

The tubules sense compounds the body doesn't need,

肾小管检测出身体 不需要这些化合物

like urea, left over from the breakdown of proteins,

如尿素，蛋白质分解 遗留下来的物质

and redirects them as urine out of the kidneys

并重新安排它们 成为尿液排出肾脏

and through two long sewers called ureters.

并通过两个长的 下水道，叫输尿管

The tubes empty their contents into the bladder to be discharged,

输尿管清空尿液 进入膀胱，尿液被排出

ridding your body of that waste once and for all.

最后摆脱那些 体内的废物

There's water in that urine, too.

也有水分在尿液

If the kidney detects too much of it in your blood,

如果肾脏检测太多 废物在你血液中

for instance, when you've chugged several glasses at once,

例如，当你同时 突然喝几杯水

it sends the extra liquid to the bladder to be removed.

这会使膀胱有额外 的液体，要被排出

On the other hand, low water levels in the blood

另一方面，水分 含量低在血液中

prompt the kidney to release some back into the blood stream,

导致肾脏释放一些 水分回到血液

meaning that less water makes it into the urine.

这意味着较少水分， 使它形成尿液

This is why urine appears yellower when you're less hydrated.

这是尿液出现较黄的原因， 当你体内缺少水合物

By controlling water, your kidneys stabilize the body's fluid levels.

通过控制水分，你的肾脏 稳定身体的流体水平

But this fine balancing act isn't the kidney's only skill.

这种好的调节平衡表现， 不是肾脏唯一能力

These organs have the power to activate vitamin D

肾脏还有能力 激活维生素D

to secrete a hormone called renin that raises blood pressure,

分泌称为肾素的激素， 这会提高血压

and another hormone called erythropoietin,

和另一种激素 称为促红细胞生成素

which increases red blood cell production.

提高红细胞产生

Without the kidneys, our bodily fluids would spiral out of control.

如果没有肾脏， 我们的体液会失控

Every time we ate, our blood would receive another load of unsifted ingredients.

每次吃东西，我们血液承受 没有经筛选成分的负担

Soon, the buildup of waste would overload our systems and we'd expire.

不久，废物堆积使我们 系统负担过重，我们会死

So each kidney not only keeps things running smoothly.

所以，每个肾脏不仅 让事情顺利运行

It also keeps us alive.

它也使我们活着

Lucky then that we have two of these magical beans.

我们幸运有两个 这些神奇的豆子