How Much of Your Body Is New Every Year? | Compilation

Certain parts of you continue to regenerate. You can regrow your liver, for instance. But why not your lungs or legs? Scientists are getting closer to solving that mystery.
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Sources:
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Original Episodes
Can We Treat Alzheimer’s With Period Blood?
• Can We Treat Alzheimer...
20% of Humans Have An Extra Spleen - Here’s Why
• 20% of Humans Have an ...
Can You Keep Donating and Regrowing Your Liver?
• Can You Keep Donating ...
Why Can’t I Grow More Teeth?
• Why Can't I Grow More ...
Can Grey Hair Be Reversed?
• Can Gray Hair Be Rever...
How Do Animals Re-Grow Limbs (And Why Can’t We?)
• How Do Animals Re-Grow...

[@outlawbillionairez9780]

My body's been trying to get rid of me for 72 years ☹️

[@elquesohombre9931]

It’s only trying to kill you to keep you alive

[@537monster]

Hope you somehow get 72 more

[@StarScapesOG]

I feel that....

[@user-bm6xz6pq5z]

​@@537monsterWhen I was a kid people were predicting that the first person to live to 150 is currently alive right now (in the 2010's 😂). Truth is though we won't know until they make it there so we just have to wait and see. 😂

[@bennypika3575]

its how you treat people that made your inner treat you the same. I mean, where else your cells get their role models from

[@Paul-A01]

"Regrowing your liver isn't as great as it sounds" -Prometheus

[@An_Iron_God69420]

lmfao but zeus gave his liver infinite regeneration. just so an eagle could eat it every morning XD

[@socrabe]

Good one! 😂

[@helenamcginty4920]

I love cross fertilisation of thoughts.

[@puperman4208]

@@helenamcginty4920that one human thing!

[@sleeptil3]

"Eager beavers"...someone on the team is VERY pleased with that line 😂

[@dswhodis]

That part of the video was from the Alzheimers vid just a couple weeks ago, it stuck with me. Its gold! Or perhaps crimson is the prize here lol!

[@cweaver4080]

I caught that too! Was lol

[@BenTajer89]

The reason we are bad at regenerating lungs, is because for most of our evolution these injuries were almost entirely fatal. The same is true for brains and hearts etc. If an injury is always lethal, there is no selective pressure to regenerate it, and regenerative mechanisms get lost over time. The very fact we can live without a spleen is probably why it regenerates so well - it is non-essential but its presence confers a selective advantage. Likewise you wouldn't last a day without your liver, but you could last a long time with maybe 20% of your liver. You can also think about how a small animal like a salamander with a low metabolism and low flow blood rate would be more likely to survive losing a leg than a human or a frog. The salamander can still slide along on its belly, while the human will bleed out and the frog will become immediately vulnerable if it doesn't also bleed out - and surprise, salamanders regenerate legs, humans and adult frogs do not. Fish and salamanders can survive some pretty major heart injuries that would kill a human in seconds (probably because their metabolisms and oxygen flux are very low compared to mammals), AND they can regenerate their hearts. I don't think this is a coincidence. This sort of removal of selective pressure is commonly used to explain many phenomena in nature, such as the fact that many rodents age rapidly and are super vulnerable to cancer because most of them die to predation before these pressures become relevant. Of course the truth is way more complicated this. For example, traumatic liver and spleen injuries that don't also destroy other critical systems are pretty rare, suggesting that maybe these mechanisms are retained because of damage from disease or toxins, or because they are pleitropically linked to developmental and regenerative processes that are under stronger selective pressure. The liver, and other organs also adjust their size (slightly) to reflect demand as part of homeostasis, so regeneration of the liver and spleen might be linked to that. I'm just one regenerative biologist with an opinion, many others would disagree with me, and that's ok, it's how science should work. A bit of shameless self promotion, my thoughts on regenerative evolution are here: www.frontiersin.org/articles/10.3389/fcell.2023.1206157/full Some other citations: Why slow metabolism vertebrates are better at regeneration pubmed.ncbi.nlm.nih.gov/32914411/ Regeneration of organs as an extension of homeostatic processes pubmed.ncbi.nlm.nih.gov/22542702/

[@user-bm6xz6pq5z]

You know that famous paradox where if you repair a boat over time until eventually every single part has been replaced with new parts, is it still the original boat? And what if you made another boat out of all of the old parts from the original, is considered that a new boat or is that the original boat? The fact that you're still you after all these years of living and your body replacing parts leads me to believe the boat is still the same boat even if its parts get changed.

[@matthewcox7985]

The Ship of Theseus, also known as "Grandfather's Axe."

[@FrozEnbyWolf150]

The philosophical argument I've heard is that the "you" is the functioning of your body, in particular your brain, not the specific molecules and atoms making up your body. As long as there is continuity in function, you're still you. When the parts get replaced, they take up the same processes as the old ones.

[@requiemforameme1]

@@FrozEnbyWolf150The real you truly is the friends and memories made along the way.

[@helenamcginty4920]

Ha. Who knew there was gender differences in old sayings. I heard it was a broom. 😅😅😅

[@viviaeve]

You are different people throughout your life, though. You aren't the same person at 10 vs 30 vs 50 in the brain or in the body.

[@matthewcox7985]

14:04 Was the rat who regrew his liver 12 times named Prometheus? 🐀

[@DiscordianDisciple27]

Accessory Spleen sounds like a good band name

[@spitfirebird]

Thank you for all the wonderful and informative videos, it’s been a fantastic 2023. Here’s to another year of amazing science videos!

[@ericbartol]

6:37 "...eager beavers..." VERY nice! 😀

[@genreofstubby]

VICTIMS OF ABUSE... Just think, one day, your attacker would have never touched a single cell of you. i find that healing

[@lucky-segfault4219]

A good scrub in the shower will remove the outer layer of your skin. So one day might be like later that week depending on how aggressive you are in a shower

[@helenamcginty4920]

​@@lucky-segfault4219back in my long ago youth showers werent a thing in the UK except in gyms (and prisons?). A nice hot bath served. Most women I knew knew the regenerative effect of this. A small comment to an understanding flat mate with an understated response was also helpfull. (We are talking England here. 😊)

[@lindatullos9430]

it''s the violation memory and taking away the choice of one's experiences.

[@emom358]

I started turning grey at 17. I liked how it was growing in, plus it has more body than the original.

[@jay88ar]

How long till I get a new lower back?

[@kraneiathedancingdryad6333]

"Monthly redecorating" 😆😆😆

[@user-co8vc5nd7l]

Thanks to all the scientists working on this and special thanks to the scientific uteruses letting humanity put their old decorations to use.

[@ecospider5]

What, flesh tones again. I really need to talk to the decorator.

[@susanduarte6888]

I’m almost 80 but my hair stayed the same color as when I was 18. I’ve a few of those wild curly grey eyebrows and plenty of age-appropriate wrinkles but no grey hair. Weird.

[@wintersnowcloud]

still a good video... but, I was kind of hoping this video would be about all the cellular turnover in a given year. Such as how many new skin cells, how many new cells in your stomach lining and just a grand total somehow of all the cells that the body replaces, on average, in a given year for an adult.

[@miriammcfarlane6972]

Me too!

[@collin4555]

Please tell me the rat in that liver study was called Prometheus

[@grantpflum6844]

To be fair, no known regeneration on earth is infinite. Even the axolotl, the creature with the best regeneration on earth that is capable of regenerating nearly half its brain, will lose the ability to restore its limbs after they have been severed enough times. Each time their regrown it becomes a little less efficient and perfect as if part of the code is lost.

[@borttorbbq2556]

Hammer head worms

[@ecospider5]

@borttorbbq2556 Thanks for the name I could not remember what it was. I think you can get over 10 new worms by cutting up just one. Each piece will fully regenerate into a new worm in a couple weeks. Supposedly they are worried the hammerhead worm will eradicate the earth worm.

[@EmpressOfExile206]

*Hydra* has entered the chat

[@Fandestdh]

Aren't jellyfish, crocodiles and sharks very much biologically immortal? Or you're talking specifically about restoring limbs?

[@borttorbbq2556]

@@Fandestdh no

[@Rkcuddles]

So glad sci show dropped the all caps style… used to never be able to read them

[@craigswanson8026]

“Eager Beavers”‼️😜😜

[@colton2307]

Now I have to look up how pineapples grow.... the thirst for knowledge is never quenched... born parched

[@lesleyghostdragon3149]

Wowzers!!! Screw all those other cool potential regenerative things! I just want the miraculous age reversal treatments Hank Green is taking! He looks fabulous!😍

[@stardewofpyrrhia4381]

This is a compilation that has old and newer videos :)

[@ElAnciano92071]

I hope you guys n gals have a sense of humor. On your bit on "donating menstual blood" you referred to those excited to do so as "Eager Bevers"! I almost fell off my chair with startled laughter! :D

[@danwooller6101]

They knew

[@EthanKTufts]

okay, which intern was in charge of drawing that eevee?

[@DogFoxHybrid]

I figure a lot of people would volunteer for liposuction if it was paid for, lol.

[@borttorbbq2556]

I would

[@judithdomangue9995]

Happy new year!

[@sheep4521]

Happy New Year :D

[@_maxgray]

1:04 The Eevee comparison was top-notch. Sure, not everyone is going to get it, but for those that do, it's an excellent and accessible example.

[@lachouette_et_le_phoque]

As someone in the other camp, I learned a thing about Eevees that way :)

[@ChadFisherCKF1]

She said "eager beaver" exactly where you'd expect. 😂

[@snellsnell7490]

Did you really use the term eager beaver in regards to menstrual cells

[@Zacharythelegend]

Just noticed this LMFAO.

[@lohphat]

“Eager beaver.” #whatisthisidonteven

[@SinHurr]

Not nearly enough if my bone aches are anything to go by.

[@pinkace]

I remember that 'multiple spleen' thing was in an episode of House.

[@lutilda]

Everyone underestimates the power of the female body & uterus. ❤

[@craz2580]

I mean, we really shouldn't, we all came out from that so we should all be grateful that a creture was able to contain and develop another creature inside itself

[@user-bm6xz6pq5z]

Go tell your mother you love her ❤

[@indradurgah8646]

Blessed are women

[@aspendrake9512]

I love seeing you and Hank revisit your rhythms and make change where needed. And that you trust that Nerdfighteria lives on without your videos shows just how strong the community is, and what strong leaders you have been-- it takes a lot to step back like that!

[@johnbillings5260]

Imagine waiting 20 years for your baby leg to come in.

[@Macachee]

Gray hair looks cool though! ☹️

[@gabiark9117]

Happy New Year!!

[@KnowledgeCat]

Thanks for an incredible year of informative and wonderful videos in 2023! Eagerly looking forward to another year of amazing science content!

[@alberton.1601]

Tks Scy, for all the 2023's good stuff! Go for 2024's!

[@richardperez649]

Excellent information !!!

[@shandimort7274]

Happy New Year! 🎉🥳🎊🥂

[@Barf]

Thanks!

[@lachouette_et_le_phoque]

Grey hair being caused by runway hydrogen peroxide could also be a part of why the stray grey/white hairs tend to have a different structure and be more brittle and less shiny/healthy/sleek in comparison to regular hair. It makes sense if you think of it as having literally been bleached in the same way that you'd bleach your hair to make it white at the hairdresser.

[@Appletank8]

what type of process do beavers use to keep growing their chompers?

[@lachouette_et_le_phoque]

They keep the same teeth, but the teeth keep growing out forever. Think of it similar as how the hair on your head grows: there are living cells at the root that create more material and push it outwards. It's called "open rooted" teeth if you want to look it up. Honestly it seems cruel that elephants don't use the same procedure instead of having to starve when they run out of teeth, but I guess just another way that evolution optimises things until they're just 'good enough'.

[@lizdeken5738]

Omg she said "eager beavers!" 😆😆😆

[@sophierobinson2738]

Do they have to wait until it trickles out, or can they suction it out? I had 7 day period. One day of regular flow, 5 days of 3 super tampons an hour during day, two changes and 2 maxi pads at night, 1 regular day. Hysterectomy was the best thing that happened to me.

[@Malphazar]

That "Eevee" scares me to my soul

[@flightattendantsteven]

Eager beaver? LOL!

[@thepolloelectrico1117]

So there's Lizzard Forrest Gump that "celebrated" new year with a legless Lizzard Sargeant Dan in a lab somewhere in the world? 😥

[@sherrihaight2724]

Eager beaver. On purpose. Gotta be. 😂

[@splitman1129]

I've never heard of an Evie 1:07

[@allissalee1039]

It’s so remarkable with the woman’s body can do I mean if it can create a being inside and fully take care of it and grow it and birth it, and then also feed it and keep it alive afterwards it makes so much sense that whatever’s going on in the uterus Could do this

[@ginnyjollykidd]

If only one could grow an extra pancreas.

[@margaretfulton9676]

Stefan your biceps are magnificent.

[@EnkiduIX]

Was the "eager beavers" line intentional? 🤔 I see your entendre and double it.

[@sabastianlove1286]

Waiting for y'all to mention the NMN molecule...

[@christopherdesantis9876]

"eager beaver" was not an accidental pun... ? Scishow comedy.

[@Seansmit23]

Can we get a spleen counter? 😂

[@brianbrandt25]

Did you know you can get a shot and grow all new teeth? A third set

[@tutubism]

i got parasyte vibes from that thumbnail

[@kyliecunnington7711]

What about medication takers? Is my blood safe to donate if I'm on proscribed medication?

[@awaredeshmukh3202]

Depends on the medication, so you'll have to check yours specifically

[@DesignWithTommy]

I see you trolled us at 26:00

[@ZacharyKeithQ]

When I heard about this I thought this would be my worst nightmare, since I love red meat... Then I discovered that I have AGS. I have grown to love turkey burgers and almond milk, but I would love to have a steak again...

[@archangel996]

Between the people who have had their spleen removed and those with an extra spleen, I wonder what the average number of spleens the total human population has? Are there more 0's or 2's?

[@awaredeshmukh3202]

One in five people have 1 or more extras, and I feel like the splenectomy rate is much lower than that, so probably the average number of spleens is over 1!

[@nascromt]

The menstrual blood MSCs is very Bloodborne. So cool.

[@amandatownsend5132]

Shoot id love to donate menstral cells i cant donate blood because of how much i lose (i become anemic) so puting my hell towards a good use wpuld be nice

[@EmpressOfExile206]

Surprised a video about regeneration mentioned *nothing* about _Hydra_ and their immortality via regen‼️

[@monk607]

Do one about powdered pigs bladder lmao iykyk

[@krispyking2450]

when i saw the title i immediately thought of the ship of theseus

[@davidhand9721]

You did not just say "eager beavers" all casually...

[@bettyswallocks6411]

What, not even if I have some fava beans and a nice Chianti? 😈🐑🐑🐑🤫

[@maremacd]

6:38 Eager beaver? Really?

[@glaucouswingedgull]

Good information, yet it fell short of what I was expecting. Some cells do continue to replace themselves and die, like skin cells. Some cells are thought not to continually regenerate and replace themselves, (nerve cells) yet I imagine that over time the molecules that make up those cells are lost and replaced. Somehow I came up with the guess that humans replace a good proportion of themselves every 7 years or so. So every 7 years or so, you morph into a new person, admittedly still hung onto the same old skeleton. That was sort of what I was expecting from this article.

[@simolanayak2370]

I wonder if the differentiation capabilities of menstrual mesenchymal stem cells play a role in teratoma development

[@robingunnarsson6412]

Yes but... How much of your body is new every year?

[@shenghan9385]

Extra spleen in humans? Is this a sci show video or blizzard animals video?

[@linkolnjell7975]

❤

[@sbic56]

Eager beavers. 😂

[@RimWulf]

And what about transplanted organs

[@jackb1969]

They should be paying for period blood. Not donating

[@n.tizzle323]

Finally

[@cityzXofXtearz]

Eager Beaver 😅

[@graysnake5332]

i love my spleeeeen

[@apathyguy8338]

Seriously you went with Eager Beaver for people who are donating menstrual blood.

[@melusine826]

Hate the animal testing, but interesting

[@firstjayjay]

😊

[@pierreabbat6157]

What's an /ivi/?

[@kraneiathedancingdryad6333]

You mean eevie? It's a pokemon.

[@borttorbbq2556]

Eevee the evolution pokemon. It's unstable DNA allows it to take many forms based on environmental conditions. When it evolves.

[@pierreabbat6157]

@@kraneiathedancingdryad6333 Ah! I don't know pokemon and didn't know how to spell it.

[@waltermeerschaert]

"Eager beavers"???

[@bigpurplepops]

Now I don’t know who picked Flareon for that first video’s script or who called a period “monthly uteral redecorating”… But whether it’s one person or the whole team you have my heart.

[@SuperHotnessJom]

New year, same me coz I’m perfect.

[@pancakeknight5099]

Why not sequence the stem cells to reproduce them?

[@lachouette_et_le_phoque]

Sequencing gives you the code, but what would you then do with it? Also the stem cell code isn't really different from the code that is in any other living cell as far as I understand. You can't really create whole living cells from just knowing the genetic information, they're really complex structures. In microbiology, even comparatively small parts or molecules are usually not economical to create from scratch, instead we tend to genetically modify bacteria so they produce whatever protein etc we need. The easiest way is to harvest them from humans as described.

[@ponyote]

Eevee

[@digger7581]

U eager beavers she says

[@limalicious]

That explains why virgin blood was so important to witches. It had so much potential in it.

[@steggopotamus]

It doesn't explain why so many cultures thought menstruation was dirty though, I'm now acutely aware that I'm bleeding out a life-saving gold mone every month.

[@limalicious]

@@steggopotamus for the same reason witches were vilified. Because wOmEnFoLk are a threat to the patriarchy.

[@lachouette_et_le_phoque]

Not really, since there is absolutely nothing special about virgin blood in comparison to any other (period?) blood.

[@limalicious]

@@lachouette_et_le_phoque did you shatter your funny bone or did your sense of humor shrivel up and d!e?

[@lachouette_et_le_phoque]

@@limalicious yo, did you get up on the wrong side of the bed today or what? Why are KZbin commenters always so needlessly aggressive

[@afoxcatartvideos4877]

Use my period blood. I have no use for them not now

[@allissalee1039]

Can I donate my own to make stem cells help my daughters, diabetes and her pancreas to make insulin?

[@timmy-wj2hc]

More research is needed, it is still in its infancy. There has been problems with stem cells because some become cancerous. Probably some rejection might occur as well in your daughter. In any case, it would be her own blood that would be used.

[@allissalee1039]

@@timmy-wj2hc understood! She is very young now as a type 1 so maybe by the time she’s menstruating it will be more developed 🙏🏻

[@apathyguy8338]

Just imagine the number of children who could be be healed except for the fact the religious think letting them suffer is the right thing? Nothing like mass human suffering to protect the feelings of somebody's imaginary friend.

[@chrisvielle6629]

I found it. Nevermind

[@DOBING-ko2vz]

Happy wheels

[@jackb1969]

Why not just pay people for embryos