Name: 【TED-Ed】為什麼我們的身體會衰老？- Monica Menesini (【TED-Ed】Why do our bodies age? - Monica Menesini)
Uploaded: 2021-01-14T06:18:53.000Z
Duration: 5 min 10 s

In 1997, a French woman named Jeanne Calment

在1997年，一位名叫 Jeanne Calment 的法國女性

passed away after 122 years and 164 days on this Earth,

去世了，她總共活了122年又164天

making her the oldest known person in history.

that a millionaire pledged $1 million to anyone who could break her record.

以致於有富翁提出100萬元的獎賞給任何能打破記錄的人

But in reality, living to this age or beyond

但事實上，要能夠活到甚至超越那個年紀

is a feat that very few, maybe even no humans,

Human bodies just aren't built for extreme aging.

人類的身體並不是被生來活那麼久的

我們最大的限度被設定在90歲左右

and how does it counteract the body's efforts to stay alive?

而它又如何阻止我們的身體活下去？

We know intuitively what it means to age.

我們都很直覺的知道老化是什麼意思

Yet finding a strict scientific definition of aging is a challenge.

要找出嚴謹的科學定義來解釋老化是一大挑戰

What we can say is that aging occurs when intrinsic processes

and interactions with the environment, like sunlight,

and toxins in the air, water,  and our diets,

空氣中的毒素、水、飲食等的處理與反應

and function of the body's  molecules and cells.

Those changes in turn drive their decline,

and subsequently, the failure of the whole organism.

The exact mechanisms of aging are poorly understood.

老化確切的運作方式仍是非常模糊的

But recently, scientists have identified nine physiological traits,

但最近，科學家發現了九種生理上的特徵

to alterations in a cell's regenerative ability

這些特徵在老化的過程中佔了很大的因素

Firstly, as the years pass, our bodies accumulate genetic damage

首先，當一年又一年過去了，我們的身體會累積基因的損傷

These occur naturally when the body's DNA replicates,

這是在 DNA 複製的過程中自然發生的

Organelles called mitochondria are especially prone to this damage.

名為粒線體的細胞器特別容易造成這種損害

Mitochondria produce adenosine triphosphate,

the main energy source for all cellular processes,

是所有細胞程序中的主要能量來源

plus mitochondria regulate many different cell activities

加上粒線體調節很多不同的細胞活動

and play an important role in programmed cell death.

並且在細胞死亡的程序中扮演很重要的角色

then cells and, later on, whole organs, deteriorate, too.

首先是細胞，再來是整個器官，都會跟著衰弱

Other changes are known to occur in the expression patterns of genes,

其他變化可以從基因呈現的形態來得知

that affect the body's tissues and cells.

Genes silenced or expressed only at low levels in newborns

基因在新生兒中多是在休眠或是只有極少的活動

leading to the development of degenerative diseases,

like Alzheimer's, which accelerate aging.

Even if we could avoid all these harmful genetic alterations,

就算我們能避免所有的基因變動

就連自身的細胞也無法拯救我們

The fact remains that cellular regeneration,

The DNA in our cells is packaged within chromosomes,

我們細胞內的 DNA 被包裹在染色體中

each of which has two protective regions at the extremities called telomeres.

每個染色體在兩端都有保護區塊，被稱作端粒

Those shorten every time cells replicate.

細胞每複製一次它們就會跟著變短

slowing the body's ability to renew itself.

With age, cells increasingly grow senescent, too,

當我們老化，細胞也會跟著衰老

a process that halts the cell cycle in times of risk,

這個過程能停止細胞循環帶來的風險

like when cancer cells are proliferating.

But the response also kicks in more as we age,

但這樣的反應隨著老化會更加劇烈

halting cell growth and cutting short their ability to replicate.

停止細胞成長並且降低它們複製的能力

Aging also involves stem cells that reside in many tissues

在許多組織內的幹細胞也是老化過程中的一環

and have the property of dividing without limits to replenish other cells.

它們有著不限次數分裂來補給其他細胞的特性

As we get older, stem cells decrease in number

當我們老化，幹細胞的數量會減少

and tend to lose their regenerative potential,

affecting tissue renewal and maintenance of our organs original functions.

影響到組織的再生和器官功能的維護

Other changes revolve around cells' ability to function properly.

其他變化則圍繞著細胞正常運作的能力

As they age, they stop being able to do quality control on proteins,

隨著老化，它們會開始無法有效控制蛋白質

causing the accumulation of damaged and potentially toxic nutrients,

造成受損的和潛在的有毒營養素的累積

leading to excessive metabolic activity that could be fatal for them.

導致過多的新陳代謝而致細胞於死地

ultimately undermining the body's functional ability.

There's a lot we don't yet understand about aging.

關於老化我們還有很多不了解的地方

Ultimately, does longer life as we know it come down to diet,

Will future technologies, like cell-repairing nanobots,

未來的科技，像是修復細胞的奈米機器人

等人工手段能夠延長我們的壽命嗎？

And do we want to live longer than we already do?

而我們會想活的比現在還要久嗎？

there's no telling where our curiosity might take us.

沒有人知道我們的好奇心會如何引導我們