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  • 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!

Hey there! Welcome to Life Noggin!


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B2 中上級

なぜ人間は体のパーツを再生できないのか? (Why Can't Humans Regrow Body Parts?)

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    Sh, Gang (Aaron) に公開 2021 年 01 月 14 日