你的身体超神奇（第二部分）：英语精读讲义

Your body is amazing.

你的身体太神奇了。

Did you know that laid end to end 講解

你知道吗？首尾相接后，

the airways in your lungs span 2400 km in length,

你肺部的气道总长可达2400公里，

which is a quarter of the length of the Great Wall of China?

相当于万里长城总长的四分之一？

Or that the nails on your dominant hand grow slightly faster? 語法

或者，你知道惯用手的指甲会长得稍快一些吗？

Hear my voice?

听到我的声音了吗？

Thank the three bones in your ear

这得感谢你耳朵里的三块骨头，

that are so small they could all fit on a single penny. 語法

它们小到全都能放在一枚一美分硬币上。

Without them, you wouldn't hear anything or be able to balance. 語法

没有它们，你什么也听不见，也无法保持平衡。

This includes the smallest bone in your body, the stapes,

其中就包括人体最小的骨头——镫骨，

while the longest and strongest is your femur, 語法

而最长、最坚固的则是股骨，

found in your thigh,

它位于你的大腿中，

stronger than steel and four times stronger than concrete. 語法

强度超过钢铁，是混凝土的四倍。

As an adult, you only have 206 bones,

成年人只有206块骨头，

but as a baby you had 300,

但婴儿时期有300块，

but they weren't so much as lost as simply fused together. 語法

与其说那些骨头消失了，不如说它们只是融合到了一起。

Your lungs are capable of inhaling 13 L of air every minute 短語搭配

你的双肺每分钟能吸入13升空气，

for a total of 8000 to 9000 L daily. 短語搭配

每天总计8000至9000升。

Now breathe out hard. 短語動詞

现在，用力呼气。

No matter how much you push, 語法

无论你怎么使劲，

there's always 1 L of air left in your lungs. 語法

肺里总会剩下1升空气。

Similarly, your stomach is never fully empty,

同样，你的胃也从来不会完全排空，

always containing a fifth of a cup of hydrochloric acid.

里面始终有五分之一杯的盐酸。

When upside down, 語法

当你倒立时，

your esophagus prevents partially digested food in your stomach 語法

食管会阻止胃里尚未完全消化的食物

from falling back out of your mouth,

倒流并从嘴里掉出来，

as it's made of muscles

因为食管由肌肉构成，

that contract in a wave-like motion known as peristalsis,

这些肌肉会以波浪般的方式收缩，这叫作蠕动，

ensuring unidirectional flow

从而确保内容物只向一个方向移动，

and making anything going in the opposite direction near impossible, 語法

让任何东西几乎不可能反向而行，

unless, of course, you're vomiting. 表達脈絡

当然，呕吐时除外。

The hypothalamus in your brain

大脑中的下丘脑

maintains an optimal body temperature of 37°C

会把体温维持在最理想的37°C，

and works with the skin, sweat glands, and blood vessels to maintain this temperature.

并与皮肤、汗腺和血管协同工作，维持这个温度。

When the external temperature is hot,

当外界温度较高时，

the blood vessels dilate in an effort to help release more heat 短語搭配

血管会扩张，尽可能帮助身体释放更多热量，

and sweat glands sweat,

汗腺也会分泌汗液，

so the evaporation cools off your skin. 短語動詞

汗液蒸发时便能让皮肤降温。

When the external temperature is cold,

当外界温度较低时，

the blood vessels constrict,

血管会收缩，

so blood flow is prioritized for the vital organs.

让血液优先流向维持生命的重要器官。

Some might say that the liver is the hardest working organ in the entire body 語氣意圖

有人可能会说，肝脏是全身工作最卖力的器官，

with over 300 functions to carry out on a near-daily basis. 講解

因为它几乎每天都要执行300多项功能。

Considering its importance,

想想它有多么重要，

it's no wonder that the largest internal organ in your body 短語搭配

难怪这个人体内最大的器官

is the only one capable of regenerating completely.

也是唯一能够完全再生的器官。

This jack of all trades 習語

这个“多面手”

filters everything that we eat and drink,

会过滤我们吃下和喝下的所有东西，

including alcohol and drugs,

包括酒精和药物，

converts glucose into glycogen for storage, 短語搭配

把葡萄糖转化为糖原并储存起来，

produces bile, which helps digestion,

产生有助于消化的胆汁，

and even stores iron in the form of ferritin. 短語搭配

甚至还会以铁蛋白的形式储存铁。

Your lungs and kidneys work together

你的肺和肾脏会协同工作，

to maintain and regulate an optimal blood pH of 7.4.

将血液的pH值调节并维持在7.4这一最佳水平。

If pH is higher than 7.8 語法

如果pH值高于7.8，

or lower than 6.8,

或低于6.8，

the result is usually death.

通常会导致死亡。

When pH rises,

当pH值升高时，

the kidneys excrete excess bicarbonate ions,

肾脏会排出多余的碳酸氢根离子，

and the lungs try to conserve carbon dioxide.

肺则会尽量保留二氧化碳。

When pH drops,

当pH值下降时，

the lungs work to remove more carbon dioxide

肺会努力排出更多二氧化碳，

and the kidneys will excrete more hydrogen ions.

肾脏则会排出更多氢离子。

Even though you have two kidneys, 語法

尽管你有两个肾脏，

each of which is no larger than a computer mouse, 語法

每个都不比一个电脑鼠标大，

you can survive with only one functioning at 75%.

但只要一个肾脏还能发挥75%的功能，你就能存活。

Inside each lies a network of 1 to 2 million nephrons, 語法

每个肾脏内部都有一个由100万至200万个肾单位组成的网络，

which are tiny filters capable of filtering

这些微小的过滤器每小时能够过滤

from 110 to 140 L of blood per hour,

110至140升血液，

meaning all the blood in your body

这意味着你全身的血液

is filtered through the kidneys 400 times throughout the day.

每天会经肾脏过滤400遍。

An adult has 5 L of blood at any given time,

一个成年人在任何时候体内都有5升血液，

which makes up 7% of our entire body weight. 短語動詞

约占人体总体重的7%。

Of course, your blood is full of red blood cells.

当然，你的血液里充满了红细胞。

Right now, there are 25 trillion of them

此时此刻，足足有25万亿个红细胞

coursing through a mind-boggling 100,000 km network of blood vessels. 用詞

正奔流在一个总长达10万公里、令人难以置信的血管网络中。

Every second, 2 million red blood cells die

每秒都会有200万个红细胞死亡，

via filtering from your spleen,

并被脾脏过滤掉，

but don't worry, your bone marrow is generating

不过别担心，你的骨髓也会

2 million every second to replace them.

每秒生成200万个新红细胞来替代它们。

Your hair is the second fastest growing part of your body, 語法

头发是你身体中生长速度第二快的部位，

capable of growing 6 in per year,

一年可以长6英寸，

though there is variation across populations, 表達脈絡

不过不同人群之间会有差异，

with male hair tending to grow faster than female hair. 語法

而且男性的头发往往比女性长得更快。

As a newborn, your lungs were filled with fluid.

你刚出生时，肺里充满了液体。

Approximately 10 seconds after birth,

出生大约10秒后，

you sharply inhaled as a response to the new environment, 短語搭配

面对新环境，你猛吸了一口气，

and your breathing process that sustains your life began.

维持生命的呼吸过程就此开始。

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一定要看看我们的最新视频，

by clicking the screen or using the links in the description,

点击屏幕或使用简介中的链接即可观看，

and subscribe for more weekly science videos every Thursday.

也请订阅频道，每周四收看更多科学视频。