你的身體超神奇（第二部分）：英語精讀講義

Your body is amazing.

你的身體太神奇了。

Did you know that laid end to end 講解

你知道嗎？首尾相接後，

the airways in your lungs span 2400 km in length,

你肺部的氣道總長可達2,400公里，

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

相當於萬里長城總長的四分之一？

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

或者，你知道慣用手的指甲會長得稍微快一點嗎？

Hear my voice?

聽得到我的聲音嗎？

Thank the three bones in your ear

這得感謝你耳朵裡的三塊骨頭，

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

它們小到全都能放在一枚一美分硬幣上。

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

沒有它們，你什麼也聽不到，也無法保持平衡。

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

其中就包括人體最小的骨頭——鐙骨，

while the longest and strongest is your femur, 文法

而最長、最堅固的則是股骨，

found in your thigh,

它位於你的大腿中，

stronger than steel and four times stronger than concrete. 文法

強度超過鋼鐵，是混凝土的四倍。

As an adult, you only have 206 bones,

成年人只有206塊骨頭，

but as a baby you had 300,

但嬰兒時期有300塊，

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

與其說那些骨頭消失了，不如說它們只是融合在一起。

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

你的雙肺每分鐘能吸入13公升空氣，

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

每天總計8,000至9,000公升。

Now breathe out hard. 片語動詞

現在，用力吐氣。

No matter how much you push, 文法

不管你怎麼用力，

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

肺裡總會剩下1公升空氣。

Similarly, your stomach is never fully empty,

同樣地，你的胃也從來不會完全排空，

always containing a fifth of a cup of hydrochloric acid.

裡面始終有五分之一杯的鹽酸。

When upside down, 文法

當你倒立時，

your esophagus prevents partially digested food in your stomach 文法

食道會阻止胃裡尚未完全消化的食物

from falling back out of your mouth,

倒流並從嘴裡掉出來，

as it's made of muscles

因為食道是由肌肉構成的，

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

這些肌肉會以波浪般的方式收縮，這稱為蠕動，

ensuring unidirectional flow

從而確保內容物只往一個方向移動，

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

讓任何東西幾乎不可能反向而行，

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

當然，嘔吐時除外。

The hypothalamus in your brain

大腦中的下視丘

maintains an optimal body temperature of 37°C

會把體溫維持在最理想的37°C，

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

並與皮膚、汗腺和血管協同運作，維持這個溫度。

When the external temperature is hot,

當外界溫度較高時，

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

血管會擴張，盡可能幫助身體散發更多熱量，

and sweat glands sweat,

汗腺也會分泌汗液，

so the evaporation cools off your skin. 片語動詞

汗液蒸發時就能讓皮膚降溫。

When the external temperature is cold,

當外界溫度較低時，

the blood vessels constrict,

血管會收縮，

so blood flow is prioritized for the vital organs.

讓血液優先流向維持生命的重要器官。

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

有人可能會說，肝臟是全身工作最賣力的器官，

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

因為它幾乎每天都得執行300多項功能。

Considering its importance,

想想它有多麼重要，

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

難怪這個人體內最大的器官

is the only one capable of regenerating completely.

也是唯一能夠完全再生的器官。

This jack of all trades 慣用語

這個「多面手」

filters everything that we eat and drink,

會過濾我們吃下和喝下的所有東西，

including alcohol and drugs,

包括酒精和藥物，

converts glucose into glycogen for storage, 片語搭配

把葡萄糖轉化為肝醣並儲存起來，

produces bile, which helps digestion,

產生有助於消化的膽汁，

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

甚至還會以鐵蛋白的形式儲存鐵。

Your lungs and kidneys work together

你的肺和腎臟會協同運作，

to maintain and regulate an optimal blood pH of 7.4.

將血液的pH值調節並維持在7.4這個理想值。

If pH is higher than 7.8 文法

如果pH值高於7.8，

or lower than 6.8,

或低於6.8，

the result is usually death.

通常會導致死亡。

When pH rises,

當pH值升高時，

the kidneys excrete excess bicarbonate ions,

腎臟會排出多餘的碳酸氫根離子，

and the lungs try to conserve carbon dioxide.

肺則會盡量保留二氧化碳。

When pH drops,

當pH值下降時，

the lungs work to remove more carbon dioxide

肺會努力排出更多二氧化碳，

and the kidneys will excrete more hydrogen ions.

腎臟則會排出更多氫離子。

Even though you have two kidneys, 文法

儘管你有兩個腎臟，

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

每個都不比一個電腦滑鼠大，

you can survive with only one functioning at 75%.

但只要一個腎臟還能發揮75%的功能，你就能存活。

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

每個腎臟內都有一個由100萬至200萬個腎元組成的網狀系統，

which are tiny filters capable of filtering

這些微小的過濾器每小時能過濾

from 110 to 140 L of blood per hour,

110至140公升血液，

meaning all the blood in your body

這意味著你全身的血液

is filtered through the kidneys 400 times throughout the day.

每天會經過腎臟過濾400遍。

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

一個成年人在任何時候體內都有5公升血液，

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

約佔人體總體重的7%。

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

當然，你的血液裡充滿了紅血球。

Right now, there are 25 trillion of them

此時此刻，足足有25兆個紅血球

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

正奔流在一個總長達10萬公里、令人難以置信的血管網中。

Every second, 2 million red blood cells die

每秒都會有200萬個紅血球死亡，

via filtering from your spleen,

並被脾臟過濾掉，

but don't worry, your bone marrow is generating

不過別擔心，你的骨髓也會

2 million every second to replace them.

每秒生成200萬個新紅血球來取代它們。

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

頭髮是你身體中生長速度第二快的部位，

capable of growing 6 in per year,

一年可以長6英吋，

though there is variation across populations, 表達脈絡

不過不同族群之間會有差異，

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

而且男性的頭髮往往比女性長得更快。

As a newborn, your lungs were filled with fluid.

你剛出生時，肺裡充滿了液體。

Approximately 10 seconds after birth,

出生大約10秒後，

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

面對新的環境，你猛吸了一口氣，

and your breathing process that sustains your life began.

維持生命的呼吸過程就此開始。

Be sure to check out our newest videos

一定要看看我們的最新影片，

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

點選畫面或使用說明欄中的連結即可觀看，

and subscribe for more weekly science videos every Thursday.

也請訂閱頻道，每週四收看更多科學影片。