SciShow Tangents - Skin

Starting point is 00:00:00 Hello and welcome to SciShow Tangents, the lightly competitive science knowledge showcase. I'm your host, Hank Green, and joining me this week, as always, is science expert, Sari Reilly. Hello. And also our resident everyman, Sam Schultz. Hello. I would like to ask you to a personal question that's become increasingly important in my life, which is, when does it stop being fun for me to be pedantic? for me to be pedantic. Because we all have seen it. We're like, here's the 93 reasons why this movie is wrong. And it's just like, no, no, no, that's not good anymore.

Starting point is 00:00:54 But there's a place for it. How do I know when I'm being intolerable? Are you asking at what age you think you'll outgrow this or in a social context? No no i need i need a boundary to stop me before i become one of those guys i see i see okay because my age where i outgrew it was like 18 as soon as i switched from high school to being in the real world that sounds like it was a big win for for you and everyone you know yeah my social and yet i'm out here analyzing the predator's face and thinking there's no way that those jaws could close because there's no there's no the

Starting point is 00:01:30 musculature isn't there on his little outside teeth yeah on the outside thin teeth i think it's maybe more fun if instead of saying this couldn't work maybe trying to explain how it could work does that make sense yeah i'd be like here's where here's where there would need to be some flesh on the predator's face in order for those outside teeth to be able to do any real damage because i'm not saying like there could be little muscles in there that could sort of like hold things in place if you don't know the predator's got two sets of teeth he's got the big outside teeth he's got little inside teeth the idea i think is the big outside teeth would like like hold on and then feed the prey into the predator.

Starting point is 00:02:08 But the real idea is that when he takes his mask off, he looks really scary to the people watching the movie. Yeah, it's good to have two sets of teeth if you want to be pretty upsetting. To double roar with. Yeah. Does he double roar? I think when he first takes his mask off, you're like, oh, this guy is not so scary. And Arnold Schwarzenegger's like, oh, I could take this guy. But then he's like, I have another mouth under my mouth.

Starting point is 00:02:30 And then Arnold's like, no way. No way. The aliens have two mouths, too. They do. That is an interesting parallel. Yeah, which I think happens sometimes in nature. Like, aren't there some animals that kind of have a second set of teeth? There are animals with multiple rows of teeth.

Starting point is 00:02:46 Like, sharks have multiple rows. But I don't know if there's, like, a second jaw within a jaw. There's some fish that have, like, a mouth that bites, and then inside of their throat, they have, like, grinders. Yeah, they got some more teeth down in there. Sort of an extra set of,

Starting point is 00:03:01 like, doing mouth-like work. You're right. Pharyngeal jaws in a moray eel. Don't put your hand down in there. No. Don't put your hand deep into an eel. See, now it's fun because you're teaching us something. Right, right. And then there's that.

Starting point is 00:03:13 I saw the tweet about this and it said, when the jaws open wide and there's more jaws inside that samore. Which is my poem for that. No, it's not. Anyway, we're here on SciShow Tangents. It's a show where we get together to try to one-up a maze and delight each other with science facts while also trying to stay on topic. Our panelists are

Starting point is 00:03:35 playing for Glory and for Hank Bucks, which I will be awarding as we play. And at the end of the episode, one of them will be crowned the winner. But to start the episode out, after you guys have made me feel a little bit better about myself, we're going to have a science poem this week from me. An important thing when life begins is to keep outside out and inside in. That's really almost the whole basis of a little thing we call homeostasis.

Starting point is 00:03:59 There's a border between living and dead, between what you see and the eyes in your head. For you, it's about two square meters from the top of your head down to your feeders. The largest organ you have in your body. Yet if... The largest organ you have in your body. Yet if I can see the whole thing, it's a little bit naughty. Keeping the outside in. Keeping the outside out and the inside in.

Starting point is 00:04:21 It's all eight pounds of your wonderful skin. side out and the inside in it's all eight pounds of your wonderful skin that was good because you gave no indication that you were about to do a silly rhyme like feeders and up until then it was so straight legs well i was having a problem all right yeah there's not a lot that rhymes with meters and i wanted to i wanted to talk a little bit about the the sort of specifications of our topic for the week which is skin sari what is skin it is an organ it is a protective organ and it has a lot of other stuff in it but skin is only skin on vertebrate animals which i thought was interesting uh so like biologically speaking skin is skin and vertebrates and it is not scales it is not feathers it's not hair okay what right right right yeah okay but all those things have skin

Starting point is 00:05:10 but birds have skin underneath yeah invertebrates either have like an arthropod exoskeleton sure or a shell or if you get to the gushy bits that are like a slug or a snail or a sea cucumber that's just tissue i don't think it's specialized enough to be considered skin like a barrier right like a jellyfish doesn't really have skin it's just like uh just got goo the tissue actually has to be different from the other tissue in some way so one thing i i know uh from teaching anatomy and physiology even though i was not very qualified to do that, is that, so there's epithelial cells is like the kind of cell that we have in our skin.

Starting point is 00:05:51 We also have it in non-skin places. We have it sort of on all the places that sort of experience the outside in some way. And so I'm curious, at the points where we transition from having like the keratinous, like the place where the epithelial cells, like, leave behind dead, like, hard keratin stuff that is the stuff that, like, makes up skin that's, like, hard and is hard to, like, cut through or scratch through. Versus, like, the inside of our lungs, which do keep outside out and inside in.

Starting point is 00:06:21 Like, they're still doing that work. Or the inside of our digestive systems, which our digestive systems are covered in epithelial cells but like it's not really skin it's wet it's delicate you could easily scratch it and and have it bleed uh what it is basically i'm asking is my tongue covered in skin it's my throat covered in skin it's my rectum covered in skin it's my colon covered in skin it's gotta beum covered in skin it's my colon covered in skin it's gotta be more like a slug right your rectum and colon is a slug and that's tissue is that right that's what i would think not that it's a slug but that it's like a separate tissue that my rectum is not a slug

Starting point is 00:06:57 your rectum is a hollowed slug yeah yeah uh which is basically a worm no i think it's because it like your tongue is an organ and it's muscle tissue in the way that like your heart is muscle tissue or your intestine is it is epithelial cells but it's different than the epidermis it's a muscle covered in epithelial cells which is just like my calves too yeah but there's other stuff the composition of their epidermis is different than the composition of your tongue in that it has elastin and keratin and other proteins in it and glands so sweat glands sebaceous glands like oil glands um hair follicles and layers like that that you don't have present in other organs and I think in the way that an organ is a collection of similar tissues,

Starting point is 00:07:46 your skin has those elements as a part of it. Right. I bet that there are some people who would argue that all of the whole digestive system is kind of skin. And I would love it. To what end though, Hank? This is your new, is butt legs, is lip skin. Where does your skin stop?

Starting point is 00:08:04 And where does the rest of your inside begin? Is rectum skin. So, Sari, I feel like we got a fairly good idea of what skin is. Do you have anything else to tell me about it? I do. I have some word origins because it's kind of a mystery. A linguist said the answer lies hidden in the depths of civilization. Sure, sure. That sounds right for a lot of these things yeah but as far as i can tell there are two different words

Starting point is 00:08:32 for like the covering of our body uh one category of them so the the root word of cuticle and the root word of hide like the hide of an animal are the same uh which is s-k-e-u which means to cover or conceal so it's like the idea of this this coating that is concealing you and uh it's like your outer layer that makes sense in the way that we refer to like a cuticle mostly like an insect cuticle or something like that. But the word dermis or like any sort of dermatology, dermal, epidermal, and the word skin both come from root words that mean to flay or tear or cut, which is like a very violent origin and action. Right, like the verb to skin.

Starting point is 00:09:23 Yes, like the verb to skin. Yes, like the verb to skin. And I think that's because as we trace these words back, they kind of converge with the idea of, like, human skin is equivalent to non-human animal skin. And the way that we process that was to, like, cut it and flay it and turn it into clothing and we just used the same word even though we didn't cut and flay humans as often i guess it did happen humans are violent to other humans less frequently but yeah but we're like oh we're made of the same exception to the rule so it's the stuff that tears it's the stuff that can get split we had the we we had a word for the thing that was useful and the the process of acquiring the thing that was useful. And they were like, oh, I guess we need a word for this.

Starting point is 00:10:10 Now we'll use that one. The doctors need a word. Here you go, doctors. Yeah. And then from there, I think once we had the word for human skin, then skin was then extrapolated even further. So we had animals first. And then we were like, oh, we're an animal. We have an outer layer that can be flayed. And then we looked at pudding and we're like oh that's a

Starting point is 00:10:29 skin or like this fruit like oh that's got a skin too i guess yeah yeah it became any old any old soft covering yeah okay ew um now that we know what we're talking about it's time to move on Okay. Ew. Now that we know what we're talking about, it's time to move on to the quiz portion of our show. Today we're going to be playing Skin Truth or Fail. Being self-conscious about your skin can feel like a very human experience, but actually other animals have to contend with the superficial issue of how their skin looks to potential mates, and also to predators, and even to prey. The following are three stories of animal skin, but only one of them is true. Which one is it?

Starting point is 00:11:10 It could be fact number one. Fish scaled geckos use their large overlapping scales to gather and store future meals, luring unsuspecting insects with scents produced by their skin and trapping them with their scales until they scratch their meal out. Lovely. Or it could be fact number two. When trying to attract female bats, the male wrinkle-faced bat covers the bottom half of its face with a flap of white furry skin that they only take down when it comes time for copulation. Great. But that could be fake. It could be fact number three.

Starting point is 00:11:47 To ward off sharks or other predators, the octopus Granolodon pacifica, maybe, craft fake warts out of ocean debris with the goal of making their skin seem infected and thus unappetizing. So it could be fact number one. Geckos trapping their meals with their skin and scales. Fact number two, ugly bats using a face mask of skin for mating. Or fact number three, creative octopi making their skin

Starting point is 00:12:14 warty for protection. Ugly bats. They're probably okay. I don't know. Why else are they hiding? They're just self-conscious. They're like every protagonist of a YA novel of like i'm secretly i'm beautiful but i hide it right behind my skin do you take the glasses off and it's like oh she was pretty the whole time gosh the gecko one is that it is a gecko of some sort it's a gecko that

Starting point is 00:12:40 one seems like something that we absolutely would have made an episode of SciShow about. So I just can't believe that we... That's a dangerous road to go down. Why? Yeah. Because we're all, like, we frequently get SciShow episodes from tangents. Well, yeah, but... Happens all the time.

Starting point is 00:12:57 We would have seen this guy. I would know about him, I think. A little guy who keeps snacks under his scales. Yeah. A little, like a top pocket but yeah a bug scale you just i would have seen this by now so the octopus one not to tip my hand too much that one seems like it would really require an understanding of like disease like what what being sick means and stuff on the part of the octopus i guess not really it just it just on the part of the

Starting point is 00:13:26 shark like if it works then the octopus is gonna eventually maybe figure it out but the shark does need to be like ew gross i don't want that gross octopus and i could see it being an extension of camouflage in some way like octa octopi octopuses already change skin texture when they can or cuttlefish do i think some sort of cephalopod can change skin texture and so i could see them also modifying that with like i'm gonna stick some sand on me stick some rocks on me and it works for some reason but and and like the humans are extrapolating that it looks diseased rather than the octopus headed into it with that mentality of like don't let me go to school today don't eat me please i just don't think sure i also don't think sharks are discerning

Starting point is 00:14:21 enough eaters for that to matter but i don't't know. I don't know anything about sharks. But all that being said, I'm going to go with whatever the middle one was. The bats? Yeah, the bats. Yeah, the bats with the masked bats. That seems very not real also, but oh well, I've already decided. I don't like choosing the same thing as you, but I'm also leaning towards the bats because it feels like something unnecessary. There's so many things that feel like unnecessary mating rituals.

Starting point is 00:14:49 Like, ah, I just have like a big green feather. Oh, look at my large black wings. All of the dumbest things are sexual selection. Yeah. And so it'll be like, oh, he has a very good face flap. And it stretches so big. It covers so much of his head. That means biological fitness, maybe.

Starting point is 00:15:12 So I think it's that one. And bats have really fucked up faces anyway. So they probably, you know. Again, you don't even get onto the bats. These are wrinkle-faced bats, though. And if you Google them you you will see uh that if they're not traditionally attractive um they're cute um are they no they're horrible they look like the predator but with only one mouth they're a living nightmare

Starting point is 00:15:38 yeah they are very sort of like roar shock test of a face yeah that's not what you want for your face generally no i don't want it for my face but i think it it reminds me of being cute in the way like a pug is cute where it's like oh you feel a little bad for it yeah no there's too many ridges on this guy yeah that's that's a face only uh uh echo locator could love um and the fact you guys is true two winners doesn't happen often yeah i can see a little flappy right here you can see a little flappy so uh wrinkle-faced bats live in forests in mexico central america venezuela and trinidad and tobago but sightings of them are very rare so bat researchers were excited in 2018 when a pair of nature guides stumbled on a rare group of them. When the researchers went to watch them, they found that there were as many as 30 male bats perched in a group trying to attract a mate.

Starting point is 00:16:33 But, oh god, they're lecking! Lecking also is a thing that when males gather to display to a smaller group of females, you get so many weird situations of display. It's always the weirdest displays are from licking males. Anyway, what is especially weird is that while they were trying to grab a female bat's attention, the male bats would cover the bottom half of their face with a weird flap of skin covered in white fur, and then they'd chirp through the mask.

Starting point is 00:17:03 The skin-faced mask would remain in place until they found a mate, at which point the bat would lower their mask until done. Female bats do not smell. That's what it says. The female bats don't have the mask, and researchers aren't quite sure why the male wrinkled-faced bats have this mask. One theory is that it could be a way to signal females that they are ready for mating,

Starting point is 00:17:26 or it could be a way to trap olfactory secretions that will be released during mating. So just get all the secretions all jumbled up and held in there until it's time. Unfortunately, it's been hard to find these bats again since the 2018 sighting, so it may be sometime before we know for sure. So the geckos is very

Starting point is 00:17:47 weird. We almost could have used this as the fact because I think it is significantly weirder. It was so weird that, I don't know, maybe you wouldn't have guessed it, but there are fish scaled geckos. They are notable because they have very large scales that can reach up to around 8% of the gecko's body length and unlike other geckos whose scales lay flat against their bodies these scales are super large and they're only partly attached to the body and the scales are notable because one species has been observed jumping out of them when trying to escape predators when a predator grabs the gecko, it can jump out of the skin holding its scales into skate, and then it

Starting point is 00:18:28 will regenerate the scales and the skin. And I'll put a for our video viewers, put a picture of this up if we can get one. I'll find one. Because it is awful. They look like Oh, it looks like a chicken. Like a little chicken breast.

Starting point is 00:18:43 Like a little chicken breast. Yeah, it just looks like a chicken like a little chicken breast my little chicken breast so just horrifying horrifying animals for this episode of tangents they're so cute when they have their skin on yeah then they're just like whoops yeah which is true i mean it's true for most things when you lose your skin you get a little less cute significantly less cute yeah i suppose so as for the octopuses there are there are warty octopuses but this is only notable they have like really little ones because it's a way to differentiate between two very similar species of pacific ocean octopuses but no no fake warts just ward off the sharks sharks Sharks ain't doctors. They're not going to know.

Starting point is 00:19:26 They don't have any idea. All right. It's one to one. We're going to take a short break, and then it will's time for the fact off. Our panelists have brought science facts to present in an attempt to blow my mind. And after they have presented their facts, I will judge them and award Hank Bucks any way I see fit, with preference going to those who are giving me good topics for SciShows and TikToks. But to decide who goes first, we have a trivia question.

Starting point is 00:20:10 Are you ready to answer it? Yes. This is my favorite part of the whole show. Sebaceous glands are small glands in mammalian skin that open up into a hair follicle. These openings also serve as a way for the body to release sebum, a mixture of fats and cellular debris that keeps our skin from losing too much water. These glands begin forming

Starting point is 00:20:31 when we are developing as a fetus, coming after the formation of hair follicles and epidermal tissue. What is the earliest point in weeks of fetal development at which these sebaceous glands begin developing? Sam's over here multiplying nine by four. Yeah, I don't know that, first of all.

Starting point is 00:20:51 I have so little experience with babies and pre-babies. I'm going to guess 22 weeks. Okay, 22 weeks. These usually get picked when the answer is shocking. So I'm going to say like 32 weeks. Oh, like really late. Yeah. I thought you were going to go a little earlier.

Starting point is 00:21:15 I thought you were going to go. Sarah's going to run away with this one because it's 13 to 16 weeks of fetal development. After we're born, we don't usually develop new glands. Instead, they just get bigger as we get older. So they're in there ready to go. So we've got all of our sebaceous glands, which is wild because we get quite a bit larger. We get so big, yeah, but we just still got a lot of holes, the same holes. Yeah, a lot of holes.

Starting point is 00:21:47 Don't say that. Well, you know, we just have the one mouth, so at least there's that. Okay. I'm hungry. I would like a pocket cookie right now. I'm also really hungry. All right. Sarah, do you have a fact that can make me not hungry anymore?

Starting point is 00:22:08 Oh, no. It may make you thirsty so i'm ready to go first all right you want to go yeah straws and other kinds of drinking tubes are marvelously convenient invention have soda in a cup that you want in your mouth suck it through a straw have water in a backpack that you want in your mouth, suck it through a straw. Have water in a backpack that you want in your mouth, suck it through a rubber tube. Even trees kind of have straws inside them. Their xylem extends from their roots to the leaves and they create suction to help draw the water up. But humans aren't the only animals that have figured out the power of the straw.

Starting point is 00:22:37 And in fact, some lizards basically have a bunch of straws in their skin. The thorny devil is one of these lizards a super spiky ant eating reptile that lives in the australian desert the morphologically weird things that we can see are the keratinous spikes all around its body but those are covered in a watertight layer of skin called the oberhautchen which i think is great. German scientists got there first. And a layer of small scales. And if you take a closer look, like with a microscope, beneath their scales, shaped from the skin cells of the Oberhautchen,

Starting point is 00:23:23 there's a network of 5 to 150 micrometer-wide grooves, all leading right to their parched little mouths. And so even without suction, water can sort of crawl its way along certain surfaces, like partway up a straw or along a paper towel. This is called capillary action and is because water molecules are pretty good at adhering to other surfaces and cohering to other water molecules. So when a thorny devil stands in some wet sand, the water travels through capillary action into those grooves in its skin and eventually to its mouth. And when researchers have plopped thorny devils in little puddles of water, they just sort of stand there and open and close their mouths because they're drinking with so little effort. Like a beer can hat, but built into their body and the beer doesn't have to be in cans. They just got to stand there.

Starting point is 00:24:05 And this so-called skin capillary system has been measured to contain water that amounts to around 3.19% of the thorny devil's body mass. And it works no matter where the water hits their body, which is why these reptiles rub their bellies in dew-covered sand and flick it on their backs, in dew-covered sand and flick it on their backs, not for a dust bath, but to prime their skin with water so that they can suck up even more, thanks to the stickiness of water molecules. So it's not easy living in a dry, dry desert and conserving water, but apparently, having skin straws is one way to do it.

Starting point is 00:24:36 Aw. That's awesome. They look great. Is there any... The thorns have nothing to do with this. No. Surprisingly, they don't they those are all just like i think intimidation factor maybe something to do with eating works for sure ants yeah but it's all beneath beneath the thorns beneath the scales it's in their skin

Starting point is 00:24:59 that this is happening in the skin how does it get to their skin if it's beneath all their scales i think there's gaps in the scales like they're not they're not as uh tossing them away as the fish scale gecko but they're not like totally locked together like body armor because their pointiness keeps things away probably if i was gonna be some kind of species from another planet, I think I might like to look like that. Just like a big guy who looks like that? Yeah, I could just walk around on two legs. That would be pretty cool. Just like super scaly and thorny.

Starting point is 00:25:34 And also, if I want a beer, I just pour it on my back. You could sit in a big puddle of beer and drink it to your butt. It's just you sitting with your mouth opening and closing. Nop, nop, nop. It's like I get out with my father-in-law, put my hand in the beer. Nop, nop, nop.

Starting point is 00:25:54 That was good. Alright, that was great. Sam, what do you got for me? Oftentimes, a luxury beach vacation will include a visit to the spa where your skin is pampered by things like seaweed wraps, pumice stones, lotions, little cucumbers on your eyes. I've never been to a spa, so this is just kind of what I guess it's like. Yeah. You ever been to a spa, anybody? Oh, no.

Starting point is 00:26:19 But I've never gotten any of that. Never got the cucumber eyes? Just a back rub. forgotten any of that never got the cucumber eyes just a back rub well anyway there are some creatures for whom every day seems like a luxury beach vacation like dolphins for example and according to a may 2022 paper they also may be treating themselves to the occasional spa day a diver and dolphin researcher named angela ziltner has been observing dolphins in the wild for a long time. But when she was diving in the Red Sea, she noticed the dolphins there were doing something that she'd never seen before, rubbing and scratching themselves on coral. This isn't

Starting point is 00:26:54 totally unheard of behavior incitations, but dolphins are not observed doing it very often. And as Ziltner watched them more, she noticed that they weren't just scratching willy-nilly like a dog scratching his butt on the carpet or something they were rubbing very specific areas of their body with very specific types of coral so coral is super weird to me at least and that it looks like rocks but it ain't rocks and one of the least rock things that it does is excrete mucus and it does this for lots of reasons like to avoid drying out if it finds itself above water somehow, or to block UV light, or, and this one's important, as protection against outside pathogens and sediment. And what is a dolphin if not a big, weird, sedimenty pathogen, if you really think about it? So the researchers got really up close to dolphins rubbing themselves and noticed that as they rubbed the coral started producing mucus

Starting point is 00:27:45 that would end up smeared all over the dolphin and they seemed to use two different types of coral to treat different types of skin brushy gorgonian coral for sensitive spots and a type of large ridged leather coral for harder areas like their foreheads and both types produced mucus when rubbed so they took the coral back to the lab and found at least 10 compounds in them with antibacterial effects and 17 total compounds that are hypothesized to do things like balance a dolphin's skin microbiome hydrate their skin or improve the elasticity the researchers also observed these dolphins visiting the coral after waking up from a nap like they were waking up in the morning and gonna go take a shower but

Starting point is 00:28:24 just at the coral and they'd even line up and wait to use the coral and like wait their turn for it so the next step of the research is figuring out if this is a natural impulse like the aforementioned dog butt scratching or if dolphins know that the coral contains some kind of medicinal thing and seek it out consciously but i mean either way we can find yet more commonality with the animal kingdom and our mutual urge to hit the spa and treat ourselves are the corals okay i don't know sometimes i said that they got so excited the dolphins that they would like bite chunks off the coral and go like woohoo my head feels so good yeah that they like really would get amped when they were visiting this coral.

Starting point is 00:29:06 So probably not. You know, sometimes you get in the back rub and you just kind of like, just let them have it. Yeah, I suppose. What do you mean? Just punch them in the chest. Yeah. Be like, oh, that felt good. Woo!

Starting point is 00:29:19 I would guess the coral. You grab the oil and just sort of sling it around the room. I guess the coral doesn't love it. I suppose. I know. It guess the coral doesn't love it. I know. It seems like it might be a little. Well, it's producing the mucus to protect itself. Yeah.

Starting point is 00:29:31 And it often is like, yes, more. This is what I want. The good goo for me, please. Give me that goop. This is one thing we should remember. That other animals will totally exploit nature if given the chance. Sure. We're bad, but everybody would be if you like let dogs have as much power as we do they'd wreck the whole that would be a really big disaster sure no doubt

Starting point is 00:29:52 now the second to protect the corals if this is a problem yeah can we just put like some good lotion down there oh the other thing i'm worried about is if people are like like you know that it were like three like telephone messages away from the beauty industry being like dolphins yeah i've been using this since the dawn of time to soften their supple foreheads yeah and now you too can have a soft dolphin forehead that's no good if only we just irritate coral industrially yeah yeah i was thinking that as i was reading it maybe we need to censor this episode so that the secret is not but it's like say if anybody does this you can come back here and know that we preemptively called them a bad person. Yeah. So I have to choose between our two facts, which are thorny devil with capillary skin action

Starting point is 00:30:51 or dolphins having spa days. Everybody loves dolphins. You guys are tied right now too. Everybody loves dolphins. Everybody loves coral. Everybody loves straws. loves coral everybody loves straws everybody no everybody hates straws that's true everyone hates straws but maybe that's a but it's an eco-friendly favor it's like here's a new way to do straws

Starting point is 00:31:15 you don't you don't have to use a straw you can just kill a lizard what's just more fat oh it's the lizard like i like there's been a number of times i've heard about dolphins like doing weird tool use yeah and so i'm a little bit more used to it whereas a lizard that can drink just by sort of like bellying up to a moist patch of sand and then making its mouth go funny that's just funnier and it's more surprising i I'm sorry, Sam. Sarah is the winner of today's episode of size show tangents. Thank you. Judgment is slipping.

Starting point is 00:31:53 All right. Well, that's an extra Hank buck to Sarah. No, yeah. Yes. You can't give Hank bucks in anger. All right. That means that it's time to ask the science couch where we answer listener

Starting point is 00:32:04 questions for our virtual couch of finely honed scientific minds. Vita Bjornan on Discord asks, is the skin on different parts of your body different like big skin moisturizer wants us to believe? My wife has an entire skincare routine, and I use the same soap for my head, face, body, and teeth. Not actually teeth. It's great news and there's on dolphins at least we just learned huh yeah i got different forehead skin for sure on a dolphin uh

Starting point is 00:32:31 yeah skin is different on different parts of the body uh and that's all i know it does vary across your body uh it's not just big skin moisturizer it's big anatomy and physiology they want us to believe it too there are generally two types of skin but then of course there are subcategories but it's there's like the thin skin that has a lot of like a variety of glands and hair follicles so like thin and hairy is how one one source described it and then the and then there's the rectum yeah well thick and hairless there's the other uh which is like hands feet uh face is kind of like thin like mixture i don't know lips you say thick and hairless hairy yeah i guess yeah thick and hairless uh but yeah it's like depends on what the skin is what the skin's main purpose is like is it

Starting point is 00:33:34 for protection or is it coming into contact with other surfaces like paw pads do or our hands and feet do yeah paw pads right and the different areas of our body have different like compositions i mean you can look at like how hair follicles differ across skin like that's the most visually striking difference in different parts of our skin is the different kinds of hair follicles that grow but when you look at the glandular level as well um then there's quite a big difference. So like your hands and your soles of feet don't have any sort of glands except sweat glands. So they're really good at getting sweaty, but they can't really get oily. They can't really get hairy. They can't get smelly in the same way.

Starting point is 00:34:17 Because they don't make the sebaceous stuff. Yeah, they don't make the sebaceous stuff. And I don't think they have the the apocrine sweat glands which are the the smelly ones that are in like right armpits uh genital area puberty places the sari did kind of just say that feet can't get stinky they can they can't differently yes they just get differently they get stinky because all your sweats there and then there's bacteria it's not because all your sweat's there and then there's bacteria. It's not because the glands are... And skin cells. And skin cells, yeah.

Starting point is 00:34:47 The bacteria are making it sweaty as opposed to the sweat being smelly in and of itself, I think. I think even in the case of apocrine glands, it's mostly what you're... I think mostly what you're spelling is the bacteria, the byproducts of the bacteria consuming the the stuff that the african glands make yeah i think so is it okay to use the same soap on your whole situation i think that i think that there are small differences that probably matter a little bit um and i definitely have been criticized for using body soap on my face, but I still do it. Yeah, I think it depends on what you put your body through. And also, so much of skincare is advertising in some way, like companies trying to make

Starting point is 00:35:40 us feel self-conscious about a thing to then fix that problem that wasn't necessarily a problem. And so, yes, there are different treatments for different parts of skin. And I like to default to medicine because that feels more concrete than like something subjective like acne in a non-medical sense. Acne in a non-medical sense, but like aloe vera, for example, has been used for centuries upon centuries of human care for like burned skin or dry skin because it's mucusy. And we already produce mucus to help moisturize things. We produce oils and other things. So like adding that onto your skin helps fix a problem that you identify with either your environment or like some damage that you caused. So in that way, skincare is a science. And so much of modern skincare is just like inundating people with products.

Starting point is 00:36:37 And so the people who are doing the real science work are everyone with their little spreadsheets of like, okay okay what does this do to this kind of skin yeah it's it's also very personal like different like skin is very like individual people's skin is all very different so like the the kind of idea the especially the idea that one person would say to another person you're doing it wrong is i think uh something to avoid because we are all, all have our different situations. And if it's working and it's not too expensive and it's, and it's not a, it's not like a clear placebo effect.

Starting point is 00:37:16 I think that's fine. All right. Thank you for your question. Vida. If you want to ask your question to the science couch, you can follow us on Twitter at size show tangents. We tweet out topics for upcoming episodes every week. Or you can join the SciShowTangents Patreon and ask us on Discord.

Starting point is 00:37:30 Thank you to AtOrganicBypass, AtHowAboutThatJazz, and everybody else who asked us your questions for this episode. If you like this show and you want to help us out, it's super easy to do that. First, you can go to Patreon.com slash SciShowTangents to become a patron and get access to things like our newsletter and our bonus episodes. You can also watch us on YouTube at youtube.com slash scishowtangents if you like it that way. But whichever is great. Or both. Or both. That might be a bit much.

Starting point is 00:37:59 You can also leave us a review wherever you listen. That's very helpful, and it helps us know what you like about the show. And finally, if you want to show your love for SciShow Tangents, just tell people about us. Thank you for joining us. I've been Hank Green. I've been Sari Reilly. And I've been Sam Schultz. SciShow Tangents is created by all of us and produced by Sam Schultz, who edits a lot of these episodes, along with Seth Glicksman. Our story editor is Alex Billow.

Starting point is 00:38:20 Our social media organizer is Paolo Garcia Prieto. Our editorial assistants are Deboki Chakravarti and Emma Dowster. Our sound design is by Joseph Tunamedish. Our executive producers are Caitlin Hoffmeister and me, Hank Green. And of course, we couldn't make any of this without our patrons on Patreon. Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. but one more thing parasitic blow flies lay eggs that hatch into maggots that burrow into an animal's skin causing an infestation called a fly strike that's the real name for it the stuff of nightmares my friend of mine had one of these and she taught she just loved to she loves to tell the story it's her favorite thing and i'm like no one else likes this uh this is especially a problem for Merino sheep.

Starting point is 00:39:27 So not just my friend, Bethany, but also for Merino sheep who grow so much fluffy wool on their butts that poop and pee gets crusted on and it attracts blow flies, causing nasty infestations and even death. Oh, no. So a common but controversial way that Australian shepherds have managed fly strike is by, I don't know how to pronounce this word, mulesing, M-U-L-E-S-I-N-G, cutting away crescent moon-shaped slices of skin off of sheep butts so that it grows back as scar tissue without hair follicles.

Starting point is 00:40:00 These bare butts without poop stink are much less likely to be appealing to blowflies they cut their butts off i hate that a lot that's really horrible hair off there's got to be a better way australian shepherds there must be a better way oh get them diapers

SciShow Tangents - Skin

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