中級 美國腔 10664 分類 收藏
開始影片後,點擊或框選字幕可以立即查詢單字
字庫載入中…
回報字幕錯誤
Hey there! Welcome to Life Noggin!
Have you ever wondered if it was possible for humans to regrow body parts?
Why is it that when a person loses an arm,
only the wound is healed rather than the body regrowing their lost limb?
In the spirit of Dr. Connors, let's find out.
I just hope we don't all turn into Spider-Man villains.
So humans can't regrow their own limbs, correct?
Well, that might not be entirely true.
As an embryo, long before your birth,
you may have had the ability to replace your developing limbs.
Through scientific surgery, researchers have shown that at the embryonic stage of development,
frogs can regenerate their developing limbs.
This has even been shown in mice, which like humans, are mammals.
It is yet to be proven the same with human embryos, but with this evidence,
the theory is that vertebrate embryos, including humans,
can regenerate their limbs if they are damaged or amputated.
However, other than a few special and small cases like the regeneration of fingertips,
humans don't really have this ability after birth.
But do any other animals?
It just so happens that salamanders have this super awesome superpower!
They are the only vertebrate that can regrow their limbs and many other body parts throughout their lifetime.
In fact, the axolotl, a Mexican salamander, can regenerate almost anything,
from their eyes, to their spinal cord, to even parts of their brain.
These adorable little guys are amazing!
And I want 20 of them.
So how do salamanders do it?
Well, when a human loses a limb, their cells close the wound and a blood clot forms.
This leads to a scab over the wound and an eventual scar in the place of where the limb was.
But for a salamander, scar tissue never forms—
a striking difference between their regeneration and a human wound healing.
A salamander's wound closes more rapidly and cells rush to the amputation site.
These cells revert back to a less specialized state and begin creating the blastema,
which is the bud of a new limb.
As the blastema grows, it begins to form the outline of a new limb and the foot.
The cells begin creating new tissue by proliferating and differentiating into things like muscle and bone.
The new leg lengthens, filling out the missing segments between the amputation site and the toes.
The whole process usually lasts around two months,
and then the salamander has a fully regenerated limb.
It's perfect for a cute little high five! Go science!
But in humans, the blastema never grows.
Some scientists think that's because humans don't have
all the genes necessary to facilitate such a level of regeneration.
But others think that humans don't have this regenerative ability because
it might make them more likely to develop cancers.
But even if humans could regrow their limbs, there still might be an issue.
Let's take a look back at that adorable little axolotl with the findings of two recent studies.
The researchers found that, like biological wrecking balls,
certain jumping genes need to be shackled in the axolotl's cells
or they might disrupt their process of regeneration.
They discovered that proteins found within the little water monsters allow them to prevent
these jumping genes from causing havoc.
So, regeneration is really complicated and maybe for right now, humans can't regrow their limbs.
But these studies at least give scientists hope
that we could learn better methods for treating human conditions,
like wound healing and regenerating simple tissues.
Hey, even becoming just a little bit more like Wolverine would be awesome!
I'm Blocko, and I'm the best at science communication.
And I have claws. Eat your heart out, Hugh Jackman!
So what do you think?
What limitations of humanity would you like science to be able to overcome?
Let me know in the comment section below!
Have you ever wondered why winter doesn't kill all the plants and fish? Check it out here!
Lucky for our aquatic friends, when the temperature outside falls below the freezing point of the water
only the top layer of lakes or river typicallys freeze.
As always, I'm Blocko and this has been Life Noggin.
Don't forget to keep on thinking!
提示:點選文章或是影片下面的字幕單字,可以直接快速翻譯喔!

載入中…

載入中…

為什麼四肢斷了卻再也長不回來? (Why Can't Humans Regrow Body Parts?)

10664 分類 收藏
Sh, Gang (Aaron) 發佈於 2017 年 4 月 19 日    Cloudy Wu 翻譯    Mii Wei 審核
看更多推薦影片
  1. 1. 單字查詢

    在字幕上選取單字即可即時查詢單字喔!

  2. 2. 單句重複播放

    可重複聽取一句單句,加強聽力!

  3. 3. 使用快速鍵

    使用影片快速鍵,讓學習更有效率!

  4. 4. 關閉語言字幕

    進階版練習可關閉字幕純聽英文哦!

  5. 5. 內嵌播放器

    可以將英文字幕學習播放器內嵌到部落格等地方喔

  6. 6. 展開播放器

    可隱藏右方全文及字典欄位,觀看影片更舒適!

  1. 英文聽力測驗

    挑戰字幕英文聽力測驗!

  1. 點擊展開筆記本讓你看的更舒服

  1. UrbanDictionary 俚語字典整合查詢。一般字典查詢不到你滿意的解譯,不妨使用「俚語字典」,或許會讓你有滿意的答案喔