The Skin We Live In

let me, let me have your epiderms is showing. We were just talking about this. This is this is the popular second grade, third grade joke. I guess you've got or one person comes to this is epidermousis showing and it sounds dirty or or oh what's happening something on zip to it. It's just just my skin And that's the punchline. Oh but everyone's skin is showing right right right. And here's the thing though, that that's that's the deal about skin. It seems not too exciting, the thing that

gets overlooked a punchline, but it's amazing stuff. And and as you all can tell, we are going to talk about this today. Yeah, so people probably heard this fact before, but it is in fact the largest organ human body. If you ever gone to a trivia night somewhere, they've probably thrown that one out. It's a favorite on the trivia circuit. If you were to stretch out the average adult skin, it would cover twenty two square feet two square meters and it's a little bigger than a twin bed,

and it would weigh about eight pounds. That sounds a little horrific. It sounds a little like Buffalo Bill Signs of the Lamps if you were to stretch it out. But yes, if if you were teaching my favorite at least favorite skinners in fiction, like Buffalo Bill. There's a there's a fabulous or horrifying character in Larry McMurtry's Comanche Moon who skins people. There is a terrifying skinning sequence in Murakami's which one was not the wind Up Yeah, yeah,

it is the wind Up Bird Chronicle. There's a Mongolian flair that plays a man alive, and of course fans of the Game of Throne series know the Bolton Clan rather well, it's a horrifying thing to anticipate. One more Evil Willow from Buffy someone who who does she get does somebody that someone who did something to her? Lady out? Oh yes, yes, that sin. Yeah, but obviously this was a very dramatic moment. So yeah, we're gonna talk about that. We're gonna talk about invistration. So much is just this

thing that we're wearing on us. Just flavoring the horror of being skinned kind of drives home just how important it is. It is the surface level of our being. It is the layer with which we sense the world around us. It is the layer that carries their physical identity, and we tend to have a really hard time living without it. Oh yeah, we'd be using all over. But yeah, I mean it's pretty important. We clean it, we decorate it,

we stretch it and pull it and pierce it. And in two thousand and seven, here's a nice start, eleven point seven million Americans underwent some sort of cosmetic procedure botox, filler surgery, so on. That is a four hundred and fifty seven percent increase from a decade earlier. So we're pretty concerned about how we are portraying our skin to the world. And that's not counting tattooing, right, No, exactly exactly. There's a lot associated with this. There's ego, there's beauty,

there's ritual. And here's another little fact I wanted to throw out. There are relative hairlessness is not something that is an adaptation of us wearing clothes or us having descended from dolphins. It's a it's more to do with our abundance of sweat glands. So that's why we are

the hairless wonders that we are. Some are the hairless wonders, yeah, someone others Like I was watching an older film where they had medallions the other day, and I was thinking, Oh, if the medallion comes back as a male fashion accessory, they're going to be a number of guys out there who are not who are going to lack the prominent

chest hair required to prominently display said medallion. And I was wondering if there is a business opportunity there for me in the marketing of I guess it would be like a chess market or something, a chess market chess wig, you know, because you don't want the medallion just said in there, and I just I mean, this is a good day. I'm going to say this right now, you know, Merkan hasn't come up a long time in conversation, so the fact that you just brought it up, I really

appreciate that. I'm sure there are other people out there that you just got some marking points with there. We are relatively careless, except for those who want to maybe go back to the seventies and wear medallions and put a roguain on their chest. But let's just have a little overview of how this wonder skin works for us well and why at imports. As we mentioned before, you know, without it, we would be using Clive Barkery horror shows.

And that's telling because the skin is a protective layer. You can think of it as the wall all right inside all of our guts and our bones and all this is very important. But you can think of it as like a medieval city. And we recently discussed the walls in an entire episode, and we discussed the importance of those walls surrounding that city to protect it from marauders and invading armies and barbarians. Well, same deal with

the skin. The skin is there, this is the wall around the city, and the white blood cells are the soldier is manning that wall to fight off the bacterial invaders that would come in the first line of defense on the epidermis right um. And the epidermis is also helping to produce melanin, which we'll talk about in a little bit, So we have a second line of defense.

This is the dermist. Yes, and this is like sort of the meat of the sandwich I think of it is, Yeah, I think this is where you find blood vessels, is full of collagen, which gives it the firmness that we encounter with skin. And it's also where you'll find sweat glands and the hair follicles. And it contains all these nerve endings as well. That allows to feel sensations such

as heat, cold, and pain. And as we've discussed in the past and discussing pain, when our pain sensation is working appropriately, it is an important warning sign that something is wrong, that something has pierced the defenses, that something may pierce the defenses, that something may damage the walls of our being. It also tells our immune system like, hey, by the way, we've got stuff going on, why don't

you get into the action here. Because we tried to vanquish this bacteria with our white blood cells, but you know, possibly you should get in on the game as well, right, And those blood vessels also have an important role to

play in regulating our body temperature. We touched on some of this when we were discussing the possibility and impossibility of gigantic creatures, and that was one of the things that came up and discussing like King Kong, is that you have a body that big, you've got a cooler body that big unregulated temperatures. So a blood vessels in the skin contract and dilate depending on the outside temperature.

So when it's cold outside, blood vessels contract to keep the blood near the surface of your skin from it cooming too cool. And when it's hot outside, the same vessels expand to encourage heat loss and you begin to sweat. Ah. So that's what's keeping us all nice and comfortable. And then we have the hypodermis, which is just basically attaching the skin to the bones and the muscles. Yeah, this is the innermost layer and it's just the ground level

of the skin. The tethering system. Yeah. Yeah, So our skin has to do a couple of things. That has to absorb enough ultra violet radiation from the sun to manufacture vitamin D. We your bodies really need to keep our bones strong and healthy. So I forgot the white blood cells are the soldiers manning the walls and the sea bone. They're like the outside force that kind of patrols right outside the gate. Our pores pump out this oily sea bone stuff, which is more difficult for bacteria

to penetrate. It's just another protective layer. It's a nice

little sheen on our skin. Yes, So it's doing all sorts of things, and it is also using and harnessing the power of the sun right to manufacture vitamin D. Keeping us healthy, also keep our immune systems in check, and it protects us from the damage of too much ultra violet radiation from the sun because if you get too much uvy radiation, that destroys something called full eight and fullate is really important in terms of cell function

and cell reproduction. Fullate deficiency is actually linked to neural tobe birth effects during pregnancy. That's why a lot of pregnant women take supplements for it. But this is something we're getting to you here, is this idea that our skin isn't just a protective covering, making sure that our organs don't fall out, but that there's other little nuanced things going on at the level where melanin is produced. Yeah, Melanine is a pigment that's produced in specialized skin cells

called care at incites. And the more melanine you have, the darker your skin happens to be. So hormones and genetics player role in this, and it and determines how much a pigment our bodies will produce. And it also explains the wide variety of skin tones that we have, Like you even have two siblings that share the same parents, but they'll have slightly different skin tones going on or sometimes not even so slight. And this is called the

biological adaptation. It's a trait that's evolved over time because it increases the likelihood that that person will survive long enough to produce. Professor and author Nina Jablonsky did a great TED talk about the illusion of skin color, and she talks about this fact that we are so connected to our early ancestors. We are connected by our DNA, by our mitochondrial DNA, and yet we have these differences

in our skin pigmentation. And a lot of this seems like yes, this all makes sense, but when she talks about it in this way, it's really fascinating. She talks about it by saying, let's look at what the earliest humans were dealing with in terms of their environment and why they had such a concentration of melanin in their skins. They had evolved in high UV environments in equatorial Africa.

And again it's important to drive home again, melanin helps absorb the harmful for violet rays of the sun, so light skinned people have a greater tendency to get sunburned than dark skinned people, and that's where we also see panning come into play, right, Right, so you think about

melanin as a natural sunscreen, right, Yeah. And so we're looking back at this early environment on Earth and we know that melanin has been in production for millions of years, and we've got the earliest humans hanging out near the equator and that is being bombarded the atmosphere by uv B, UV A and UVC. Now UVC is pretty much sort of being filtered out in the atmosphere, but UVB and uv A are really killing it. And v B can

be really destructive. And yet it's also really important as we've talked about and producing are helping your skin to produce vitamin deed, especially when you're dealing with early civilizations where people are not working office jobs nine to five. I mean, everyone is more or less out in the open. And if you're living in an area that's not, say, heavily wooded, that doesn't benefit from a lot of cloud cover, then you're going to be absorbing this stuff on a

verily regular basis well. And in this small concentration of area right like between tropics of Cancer and Capricorn, this is where early man is setting up shop because most of the rest of the earth is way too cold, it's way too harsh. So yeah, you're gonna have to be dealing with this environment in your skin is actually going to naturally select to pigment itself, to to create

this sunscreen for itself. But Jabonski says, Okay, what happened is that we then have migration, yes, and humans dispersed not once but twice major moves outside of our equatorial homeland from Africa and to other parts of the Old World and then most recently in the New World. And she says that when they were dispersed into these latitudes, conditions were significantly colder, of course, but they were also less intense with respect to the ultra violet regime, as

she calls it. So, over thousands of years, we see individuals move from brighter, warmer climates to colder, darker climates, and then over the course of say a single generation or even less, you will have this new migration where someone will move from these darker, colder regions right back to where they started from, more or less in terms

of heat and light within just a few years. Yeah, So, all of a sudden, you do have some of these lands opening up as the climate warms, right, and it becomes possible to live in the northern climbs, and you have dark skinned people who begin to adapt, as you say, within generations to this, and they begin producing less melanin and become lighter skinned. And I just think it's fascinating because this is the reason why we have this array of colors. And she makes this incredible point to Blonsky.

She says that we don't need a proof of concept to explain evolution that is overly complex. She says, just look at your skin and you can see the evidence of natural selection at play. Yeah, it's pretty fascinating and it really changes the way you look at different skin pigments among different racial groups that just based on where they are in the world. Well, and I think that it's given science and in particularly medicine a better understanding

of how our environment really affects our health. So if you are someone who with light skin and you're living near the equator, then you have the very real possibility that you're going to be deficient and in full eight, and so you needed to take supplements for that. If you're dark skin and you're living in extreme northern climbs, then you're going to take vitamin D because you're not gonna produce nearly enough from a week UVB coming through.

And there really a lot of us anyway in the modern world do not get in the vitamin D anyway because we, like I said, wait, now, we're living these lives where we're inside for nine to five in many cases, so we're not out in the open to receive that vitamin D in the quantities that we have evolved. Well.

In sunscreen, actually, I know that there have been some studies about the deltarious effects of sunscreen on us in terms of our immune systems and vitamin D deficiencies and even some of the things that have been cropping up, just things like allergies and kids, things that didn't used

to exist previous to like the nineteen seventies. Really because we are slathing ourselves in sunscreen, which you have to do it right, But again, if you were not really getting that exposure you need, then you can't synthesize vitamin D for yourself. Yeah, it's like you're sort of damned if you did, damned if you don't. Right, it's like, if I go out without sunscreen, I get burned. If I go out with sunscreen, then I need to take

vitamin D. So it's true. It's true. You know, I think it's time to bring the sexy on in in the form of the future of skin. But we've or we do that, yes quick, all right, we're back. So we've discussed skin, how it works, what it does, what kind of goes wrong with it as we drag it into the modern age with us. But now we're gonna

drag it even farther into the future with us. We're gonna take skin with us and try to imagine what our skin is going to be like in the years to come, all right, but this is really some very cool stuff that's on the horizon here. And before we go into that, I did want to mention that there is something that sounds futuristic that's already in playing. This is called spray on skin, and this is for burn victims. So I've mentioned that because we're going to talk about

this stuff. And you may say, I don't know if this is going to come to fruition, but things like spray on skin, or the skin gun as it's called, also seemed like it might never come to fruition, and it certainly did. So what do we get here? Well, on the and just on the subject of skin growing and skin spraying, there's an interesting project from the front

Hopper Institute of Interface Engineering and Biotechnology. They have set up a new skin factory that can supposedly produce five thousand penny sized discs of whitish translucent skin every month, and they can also do varying darker shades as well. Robots control the skin growing process, monitoring the cell broth and carefully slicing swatches to prevent infection. So this is the kind of thing we can and will use in

skin grass. You know, you have situations where someone has lost skin, particularly to burns, and what do you have to do. You have to get skin from elsewhere in the body and move it forward. That's why my friend Oz, who is shot with a flaming arrow when he was a kid, because yeah, as kids do, and so he has butt skin on his shoulder he's very proud of Yeah. Yeah, I mean because a he has it, has a story about being shot with a flaming arrow, which is which

is a pretty great story to have. And then he also has that you can talk about how it's his butt skin. But in other cases, skin is grafted from cadavers. Even so, in the best of circumstances that we're talking about a complex procedure that would be better suited if we just had some newly fresh grown custom skin on right hand, and that one too, if I remember correctly, they can actually add the pigment and they can change

the different colors of skin. There's also something using spider silk. Yeah, yeah, the scientists in Germany are using spider silk as a biocompatible, biodegradable adhesive matrix for skin repairfold. Yeah, we talked about scaffolding. When we talked about growing organs, you really need some sort of structure that's underlying all this. So they're using dragline silk from golden orb web spiders, and they wove matrices on steel frames and seated them with fibroblasts which

provided the structural background for connective tissue. And then they added skin cell progenitors and we're able to cultivate synthetic skin. Again, that's the sort of broth that you were talking about, and they were able to create dermis and epidermis, which is amazing. Now, the drawback on that is it's going to be really hard to harvest a lot of spider fibers, right, So the idea is to take these spider webs and then just sort of synthesize them and create, you know,

something similar to to this natural structure. Didn't we engineer a goat that milks spiderweb or did I dream that? I'm gonna say it sounds a little surreal, a little dreamlight. I believe this was a project that some scientists were working and I have to fact check that it's projects like that that it could also be. You know, it's like we want spider webbing to serve as a scaffolding

for these skin graphs. But if we could tinker with another animal to produce the spider like a goat produces spider web that has then used to grow human skin. I mean, that's that's kind of beautiful cycle of life. Matt our producer disagreed with that that's possible. I think. I think that if that's in your head, that that is real, then there is somewhere. But then there are also a number of more techie skin things that are

out there developing. For instance, MT engineers have built nanoparticle tattoos and these are designed to help diabetics continuously monitor glucose levels, and this flows in with some of the technology we were discussing in our contact lenses of the gods article. The idea that you would have these a little receptors and nanotechnology in the lens that could interact with the fluids on the surface of your eye and then could signal you if something was up. Similar situation

with the tattoos. You could have a tattoo in place, and you could have fluorescent dyes and sensor molecules that bind certain chemicals, and then you could flash the multiviolent light on it, and you could attact what is actually going on inside you. If you're having a right you can have an iPhone app that would send that information to a computer to be analyzed. Yeah. I know. It could be used to test for things like, you know,

to help diabetics monitor GOOGLESE levels and things of that nature. Yeah. There's also something that's really cool and it is a peelable electronic circuit skin put. No, no, no, not skin put. That's a different one. I'm jumping ahead. The skin puts really cool too, though, But that can be rubbed onto the skin just like a temporary tattoo, and the small circuits can bend and stretch with the skin, and the semiconductor circuits could be used to monitor muscle activity, hard activity,

or even brain waves. And you get it off just as you would temporary tattoo. You just kind of rub it off a little soap and water. Yeah, so almost like a patch, except even less intrusive. Yeah, but you mentioned skin put that I am the most excited about. Yeah. That's the project created at Carnegie mill And University and Microsoft Research. And it turns your arm or or I don't know, your back, I mean, but really anythings on

the table I guess into a touch screen. So in the case of your hand, you have a small arm band and a user would project an information display onto the skin, so it would be you know, projection of say a keyboard or some sort of input display, and you would press the skin like you would an iPhone

or any other touch screen. And the arm band contains an acoustic sensor that uses the tissue density and other biometric data to determine where you've tapped, So it's projecting this little keyboard onto your hand, and then the band would also detect where you're touching on that keyboard where you're on yourself. So if you think bluetooth, if you think that made everybody look insane, just wait until we get this little keyboards on our skin and we all

are poking ourselves. You know that the early adopters, at least I like the idea of that using other people's backs for it, you know, because it kind of plays with the whole deal You've seen in TV shows where somebody needs to sign a paper and they would have the person in front of them lean over so they could sign on their back. Well, and I can see that like a cheesy like sitcom plot point to take your shirt off so I can use your back is I don't know, you know what I'm saying. I don't

know it went somewhere. I didn't mean for it to go, but technology always does. It does exactly. So what about our robot friends like Arnie? What what sort of skin tents can we create for them? Oh? Yeah, there are some products that are looking into the possibility of robot skin,

which sounds very terminator ask at first. As a kid, I always found that fascinating how the Terminator he has his end of skeleton that is robotic, and then he's covered in human skin, this living human tissue because he's disguising and because whatever they're weirdo time travel system you can only send a living thing back in time or something. But I always found it interesting to think, well, how does that skin behave, how is it working? How is

it jiving with that robot underneath it. One of the big things would be that the skin is this layer of sense. It allows us to touch things and feel the environment around us. So while we're not necessarily looking to grow Arnold Schwarzenegger's skin around all of our robots. The idea of creating a skin like barrier, the skin like layer that is used to sense the world, that is very much on robotist minds. Okay, well, let me describe something to you that is extremely rudimentary version of that.

Like I even sort of see it as like a metal robot, like squirted with do Okay. Basically, a team of researchers at pit University may predictions regarding the behavior of Belosov zabatanski z gel. And that's a material that was first fabricated in the late nineties and is shown to pulsate in the absence of any external stimmy lie. In fact, under certain conditions, the gel can sit in a petri dish and resembles a beating heart. So there's

a little creepy element. And that's without scimuli. Yes, okay, so it needs stimuli to stop the pain. This sounds like a great I was about to say, it seems like you're going there with a plotline. So Annabellas, she's the Distinguished Professor of Chemical and Petroleum Engineering and Pits Swanson School of Engineering, says, think of it like human skin, which can provide signals to the brain that something on

the body is deformed or hurt. The gel has numerous far reaching applications, such as artificial skin that could be sensory, which she says is the holy grail in robotics. You throw in haptic technology for virtual reality environments and the applications there become obvious as well. We're sending, say a robotic pro about to another world, and we want to sense that world as we would sense it there physically. Didn't makes sense to have that kind of technology involved

with the robot that we sent. Well, I was thinking about that too in the context of the virtual sex episode that we did, especially with another little technology here or big technology is stretchable electronics. Yeah, and this electronic skin could bring touch sensitivity to machine. So this is a more well, I think if it is a more

sophisticated version. So the gentlest pressure that human skin can detect is about one kilopascal, but a stretchable skin can actually detect pressures that are one thousand times more gentle, like a ghost sneezing on you. Yeah, yeah, exactly. Uh. It's based on organic transistors. It's made of electric elect elastic sorry material sandwich between two electrodes, and it's a highly sensitive surface that could help robots pick up delicate

objects without breaking them. When delicate objects, I think means us right in the future. We've talked about that too. Give prosthetics a sense of touch, which would be super cool, and give surgeons find or control over tools for minimally invasive surgery. Well, there you have it. The future of skin is bright, full of that grown custom skin pulsating pulsating gel that we're spraying onto our robots. It's going to be an amazing time to live in. HM. Let's

check in with our skinless robots, shall we. Yeah? Yeah, Let's get some listener mail. All right, here's one we received from our listeners. Scott. Scott writes in and says, hey, guys, I stumbled across your podcast a few weeks ago, and I've been greedily gobbling up episodes ever since. I just listened to the Lucid Dreaming episode and I wanted to

share some of my experiences with lucid dreaming. When I first started working on the night shift as an r ND, I would have extremely vivid lucid dreams almost every time I slept. I really enjoyed my experiences while lucid dreaming, and although I could never exercise complete control over the dream environment, I could usually do things like fly, teleport through walls, and breathe underwater. Somewhat less enjoyable were the episodes of false awakenings that I begin to have after

especially stressful days. I would quote unquote way Cup lying in my bed, and then I would slowly realize that I was still dreaming. I did some research, and I found some reality checks that came in Handing jumping or skipping seemed to work especially well for me. If I was dreaming, I would leap in slow motion. If I wasn't dreaming, I would just feel a little silly. The false awakening got a little unnerving when I begin having

as many as eight of them in a row. However, false awakenings did help me learn how to recognize dreams, and now I have lucid dreams about three times a week. Thanks for the great podcast, Keep up the good work. And then he also adds, Julie, have you noticed any limits on your control of your lucid dreams? For instance, when I fly in my dreams, I find that I usually can't fly any higher than the tree tops. Can you fly? Oh I can? I can fly pretty well.

It's one of I thought it was so interesting that he brought that up because it it's variable, like it's so mental because I can get up really really really high and see sort of like what you would think of as like not the view of a state, that particular geographical area. But it takes so much effort to try to keep going higher and higher because I find that I keep dropping in my dreams, and then I have to get myself back up again. So it sort

of depends on what I'm doing. If I'm just flying down the sidewalk looking in shop windows and I need to get so high. On a related note to the dreaming, last night was the first night that I tried out this app on my iPhone called dream On like dream

cooling on. The way it supposedly works is that you turn it on when you go to bed, you haven't plugged into the wall, and you have it laying face down on the bed next to you, like at the corner of the bed, and then it will detect your motions like you can supposed to tell how much you're moving around, and then it can figure out when you're in deep sleep based on your lack of motion, and you can have it play a preset sound to let you know that this is the time when you should

be dreaming. If not alert you into a lucid state, then at least color your dreams with some sort of a soundscape that sounds like the beginnings of what we talked about the Aldge study right where they were talking about trying to influence your dreams and give you a nice dream. Yeah, and the the app had some sort of dream journal apparatus as well, because the people who made it want to sort of keep track on how people

are using it and what effect is having. I did not have any good experiences with it last night because the cat was very vocal about becoming an indoor cat. Did you dream of a goat producing spider whip milk? No? I dreamed a vote cat that was shut up for an hour straight so I could sleep. That then turned into a goat. Yeah, But I'm gonna keep trying it out and see if it does anything for me. It's a free download if anyone else wants to try it.

There are some like in app purchases if you want to get like different sounds, but you can use it as is, and you can incorporate your own music tracks off your phone without any kind of interventional price. So if anyone else wants to try it out, let me know. I would love to hear what your experiences are with it, and hopefully I'll have some sort of noteworthy dreaming experience within myself. I like this your collecting data, now, aren't you. How do you get in touch with us? Well, you

can find us on Facebook. As always, we are stuff to blow your mind on there, and you can also find us on Twitter, where our Twitter handle is blow the Mind one word, and you can also drop us a line at blow the Mind at discovery dot com. For more on this and thousands of other topics, visit how stuff Works dot com