How do lungs work? - Emma Bryce

肺在做什麼？— 艾瑪·布萊思 (Emma Bryce)

譯者: YuPin Song 審譯者: Regina Chu

Many of us have hundreds of things on our minds at any moment,

我們每一刻都在腦中 想著數以百計的事情

often struggling to keep track of everything we need to do.

通常都在想我們必須完成的事

But fortunately,

但幸運的是

there's one important thing we don't have to worry about remembering:

有一件重要的事我們不用擔心忘記

breathing.

那就是呼吸

When you breathe, you transport oxygen to the body's cells to keep them working

我們呼吸時會傳送氧氣到身體的細胞 讓身體持續運作

and clear your system of the carbon dioxide

也使體內因此產生的

that this work generates.

二氧化碳能夠排除

Breathing, in other words, keeps the body alive.

換句話說 呼吸能讓我們活下去

So, how do we accomplish this crucial and complex task

所以我們該怎麼在不自覺的情況下

without even thinking about it?

完成這重要又複雜的任務呢

The answer lies in our body's respiratory system.

答案就存在我們體內的呼吸系統

Like any machinery, it consists of specialized components,

就像任何機器一樣 它包含了專門的元件

and requires a trigger to start functioning.

也需要一個開關來啓動這功能

Here, the components are the structures and tissues making up the lungs,

而要件就是組成肺的結構與組織

as well as the various other respiratory organs connected to them.

同時也包括許多 連結到肺部的呼吸器官

And to get this machine moving, we need the autonomic nervous system,

要讓這機器運作 我們需要自主神經系統

our brain's unconscious control center for the vital functions.

我們大腦中無意識的控制中心 負責重要的功能

As the body prepares to take in oxygen-rich air,

當身體準備好接受滿滿的氧氣時

this system sends a signal to the muscles around your lungs,

系統會發送信號到肺部周圍的肌肉

flattening the diaphragm

使橫隔膜拉平

and contracting the intercostal muscles between your ribs

肋骨間的肋間肌會收縮

to create more space for the lungs to expand.

創造更多空間讓肺擴張

Air then wooshes into your nose and mouth,

空氣會咻的進入鼻腔和口腔

through your trachea,

經過氣管

and into the bronchi that split at the trachea's base,

到底部後分裂進入支氣管

with one entering each lung.

再分別進入兩個肺

Like tree branches, these small tubes divide into thousands of tinier passages

就像樹枝一樣 這些氣管又分成數以千計更小的通道

called bronchioles.

稱作小氣管

It's tempting to think of the lungs as huge balloons,

把肺想成是一個大氣球

but instead of being hollow, they're actually spongy inside,

但裡面不是空空如也 而是像海綿一樣

with the bronchioles running throughout the parenchyma tissue.

當小氣管觸及到實質組織

At the end of each bronchiole is a little air sack called an alveolus,

每個小氣管的底端都有小小的氣囊 稱作肺泡

wrapped in capillaries full of red blood cells

肺泡周圍包著微血管 裡面充滿著血紅細胞

containing special proteins called hemoglobin.

裡面包含特別的蛋白質 叫做血紅蛋白

The air you've breathed in fills these sacks,

我們所吸入的空氣會充滿這些氣囊

causing the lungs to inflate.

使肺部膨脹

Here is where the vital exchange occurs.

而這裏就是呼吸交換的場所

At this point, the capillaries are packed with carbon dioxide,

這時微血管會充滿二氧化碳

and the air sacks are full of oxygen.

而氣囊裡會有滿滿的氧氣

But due to the basic process of diffusion,

但因為擴散的基本過程中

the molecules of each gas want to move to a place

各氣體的分子

會移動到該種類濃度較低的地方

where there's a lower concentration of their kind.

So as oxygen crosses over to the capillaries,

所以當氧氣通過微血管時

the hemoglobin grabs it up,

血紅蛋白會把它捕捉起來

while the carbon dioxide is unloaded into the lungs.

同時二氧化碳會充滿肺部

The oxygen-rich hemoglobin is then transported throughout the body

充滿氧氣的血紅蛋白接著會靠著血液

via the bloodstream.

來傳送到全身

But what do our lungs do with all that carbon dioxide?

但我們的肺部該拿二氧化碳怎麼辦呢

Exhale it, of course.

當然 靠著呼氣囉

The autonomic nervous system kicks in again,

自主神經系統又一次啟動

causing the diaphragm to ball up,

使橫隔膜鼓起

and the intercostal muscles to relax,

肋間肌會放鬆

making the chest cavities smaller and forcing the lungs to compress.

讓胸腔縮小並使肺部壓縮

The carbon dioxide-rich air is expelled, and the cycle begins again.

滿滿的二氧化碳會排出 而循環會再一次開始

So that's how these spongy organs keep our bodies efficiently supplied with air.

這就是這些像海綿般的器官 如何有效率讓身體充滿空氣

Lungs inhale and exhale between 15 and 25 times a minute,

肺每分鐘會呼吸 15 到 25 次

which amounts to an incredible 10,000 liters of air each day.

很驚人的 每天呼吸的空氣總量有一萬公升

That's a lot of work, but don't sweat it.

這可是很大的工作量 但別緊張

Your lungs and your autonomic nervous system

你的肺和自主神經系統

have got it covered.

會負責完成