alright guys so this is gonna be part 2 of the integumentary system lecture all right so we're continuing on we're talking about now alright the appendages of the skin so when we think about the integumentary system right we think of our skin okay and our skin overall is an organ right so why do we considered an organ is because right there's different tissues coming together now all right to perform a common function so the main tissues we think about when we think about our skin is an epithelial tissue which is gonna be the epidermis above the way the boundary we're also gonna think about right the dermis which is a connective tissue right below the Wigner battery it's just reiterating one more time at the hypodermis is technically not part of the skin okay but since it's so closely associated we do talk about the hypodermis every time we talk about the skin all right so when we say appendages right what does that mean that means things like right hairs and hair follicles we think about glands sweat glands and sebaceous glands right we think about nails right we think about the erector coli muscle so these are all things okay that okay what we think are associated with our skin alright so the first type of appendage we're gonna discuss we're gonna talk about the Lance all right so recall it's not that far back right this class is so fast that it wasn't that far back ago when we talk about glands all right where do glands come from all right did they come from nervous tissue do they come from muscle tissue do they come from connective tissue or do they come from epithelial tissue so one of our lectures we did right was the connective tissue in the epithelial tissue lecture was at chapter 4 right so one of the slides in that particular presentation was titled epithelia and glands so I asked you back then well why are we talking about glands while we're talking about epithelial tissues well glands are derived from epithelium all right so there's two different categories of glance when we talk about your skin yeah what are called sebaceous glands and when everything about sebaceous glands you think about the glands that are associated with the hair follicle for example these would be considered sebaceous glands okay can you also talk about sweat glands yeah and sweat glands are traditionally not associated with hair follicles so here you see a sweat gland this coiled purple structure and then you see the duct that leads then to the surface of your skin alright so why do we say that glands again are derived from epithelial tissue well the reason why we say that derive from apatheia tissue is because typically when we talk about multicellular glands we think about these structures that are invaginations of an epithet okay so here's my epithelium here is my invagination of that epithet so on the basal side again we would have connective tissue right and on the apical side right would be a free space this could be all right at the surface of your body this could be the inside the movement of your stomach for example right but this is the apical surface of the epithet right and we think about right here let's just draw some epithelial cells and we think of a gland again it has kind of two parts okay you have one part that consists of cells that make up the duct of our gland right and then you think about these cells here that make up the secretory unit and we discussed in that chapter how to name these based-upon if it's a branch to run branch branch would be a compound unbranched Dunc would be simple right and then the shape of the secretory unit the ones that are shaped like grapes or help okay alveolar and the one that are shaped like tubes we call tubular so when we think about okay sebaceous glands the sweat glands okay that's exactly what they are they're invaginations of an epithet all right so the first one we're going to talk about here our sebaceous glands sebaceous means greasy all right now structure there they are simple alveolar glands meaning that it has an unbranched duct in this case the duct is actually going to be right the hair follicle we're gonna use the hair follicle to lead to the apical surface of our epithelium now in terms of the secretory unis ok the secretary units are shaped like grapes right so these are basically called simple alveolar glands right so several alveolar secretory units feed into a single dot all right now tradition when we think about AG land right glands have lumens so if I go back to our whiteboard over here all right we would consider this the lumen right of our plant okay it's a space right and traditionally these cells of the sucker 2 unit well they're gonna make a product right and that product then is secreted okay via exocytosis into the lumen of our and gland okay and because there's a duct well then we can use that duct and then our product again is what we consider locally acting okay to where it was secreted where it was produced so when we think though about right in terms of all right that space where we exocytosis and our product when we think about sebaceous glands okay the spacious lands the lumens are filled with cells okay so filling this now instead of being a space okay there are cells present within this sebaceous gland here so why is that well if we continue with our lecture all right sebaceous glands produce an oily product called sebum right and sebum the way I would like to characterize it it's our it's our body's natural moisturizer okay it you can see here it coats the surface of your skin okay it coats your hair prevents your hair from becoming dry and brittle for example right if you don't take a shower okay for a couple days what do you notice where your skin is very oily right your hair is very oily well the reason for that is because you have an accumulation with sebum now right on your hair and on your skin okay so it's our body's natural moisturizer it keeps our skin moist now it also collects dirt right it prevents water loss it also kills bacteria now what stimulates sebaceous glands to produce sebum right are hormones right so we think about the sex hormones the androgens for example they are okay they signal our sebaceous glands to makes even though we see a spike in these these sex hormones when what will when we're going through puberty so go back to when you guys were going through puberty well what did you notice well you notice that maybe started breaking out way more right you got you got a lot more pimples for example well acne right is an active infection of the sebaceous man why because those androgens okay they they accelerate these sebaceous glands produce so much sebum that it blocks the duct okay we begin to clog that duct with sebum and it becomes trapped alright and what that does well it's just basically a site where we're bacteria now okay can accumulate in that oil duct so an active infection of a sebaceous gland is actually acne right it becomes red it hurts right now ultimately what happens that the season dries and when it dries it oxidizes it becomes black okay and that that acne ultimately becomes what we consider a blackhead right and that blackhead is what we call a melanin plug all right so why is the lumen not okay empty why is the lumen filled with cells well it's because of the way that sebaceous glands produce sebum all right so here we see the secretory unit of our sebaceous gland okay and you can see the process we're gonna use mitosis right we're gonna use cell division so as the cells divide one daughter cell leaves and it enters okay this filled space and these cells now we can see the little tiny red dots here okay they produce more sebum and more sebum the more see them to the point right well they expand with sebum and ultimately these cells explode these cells blow up right and as they blow up will they release the sebum at the same time though okay it's not just sebum that's being released while you're releasing cell fragments right because you have disintegrated the entire cell so you can see how during puberty if you accelerate this process okay it's gonna be very easy to clog these pores here okay so that's why these oil glands get clogged so easily okay via this process of whole cell secretion or whole O'Quinn secretion all right the next type of accessory structure that we're gonna talk about okay still falls under the category of glands are sweat glands alright in sweat glands are spread throughout your entire body all right now it's a blood filtrate well what does that mean well it's produced from substances within your blood so if this is our sweat gland here okay notice that there are blood vessels very close by to it okay so what happens is that okay products in your blood they are used to make sweat all right now we know that the whole process of sweating is what well it's typically for thermoregulation this idea that okay sweat accumulates on the surface of our skin all right and then when that's what evaporates what happens right is that it takes the heat with it so now we have sweat on the surface of our body here alright and when this okay begins to evaporate from our body we call it a vac particular all right cuz water is a very good conductor of heat so as that water now and vaporizes well it takes out basically the heat along with it cooling our body down now how much sweat do we normally produce someone day well you probably saw when I was transitioning all right so about a bottle of water right so if you have a plastic bottled water at home okay it's around 500 milliliters and at 500 milliliters well a lot of it gets evaporated and right cools us down okay but the parts that are that are covered by clothing well then our clothes and our socks and our garments right okay soak up that sweat so it's pretty good idea to wash your clothes right now on hot days or vigorous exercise I going on a hike okay kind of Bear Grylls stuff right I'm talking about a lot of water loss right about 12 liters right in extreme situations okay that's not normal losing 12 liters of water we're very extreme situations okay you lose a lot of water alright so if if you're hiking it's not gonna be the the rattlesnake or the scorpion that gets you okay it might be dehydration okay you really need okay water right on very hot very strenuous days all right so only mammals can't have sweat glands alright only mammals have sweat glands why more because these kids used for thermal regulation used to used to cool our body down right you're gonna learn in physiology right one of the things that's kind of a central theme of physiology is this idea of homeostasis the idea of maintaining okay a relatively internal steady state right the pH of our blood the pH of our body fluids right are sugar levels all right our temperature is something that we need to regulate within a narrow range all right so on hot days we sweat we have evaporative cooling that then basically cools us down it lowers our body temperature now humans of all mammals right lions have sweat glands we have sweat glands but we have the most of all mammals right and the reason for that is because of reduction hairiness right of all the mammals and we typically have the least amount of hair right if I'm carrying a lion for example to our body right there's less hair in our body than there is on a lion so when you think about the hair on a lion you may think Oh hair on a lion that keeps it can't warm on a very cold night right well on a hot day what else does the hair do okay think about the hair on your scalp right now what is that hair doing well it's preventing light from directly hitting the sick that's at the top of your head is basically keeping your head cool on a hot day all right much like having an umbrella on a hot day right providing shade or sitting under a tree on a hot day so preventing sunlight from directly striking your scalp okay that's what our hair is used for okay and also to keep us on a cold day same thing with a line right if it's sitting out okay and it's being hit direct with direct sunlight and well it has fur it has here that then prevents that light from directly striking at skin it actually keeps it a little cool so because we have the least amount of hair what did that do well we don't have that hair to keep us cool well so what we need to do what we need to increase the number of sweat glands right so of all the mammals we have the most sweat glands because we have the least amount of hair okay so what exactly is sweat that keeps us cool well there's a type of true sweat that we're gonna talk about right it's just 99% water so mostly water and 1% salt a metabolic waste urea emmonak okay ammonia uric acid right again this is a blood filtrate so where did that water come from well it came from your blood all right now sweat is acidic so what else can it do besides just for thermal regulation cooling us down okay it also prevents or retards or slows down the growth of bacteria on the skin okay now there's two different types of sweat glands that you're gonna find on our bodies and a eccrine which is the most numerous okay and produces true sweat hey and it's something called an Apple cringe sweat gland all right which does not produce true sweat and we'll discuss what it actually produces a little bit later on now both of them respond to heat and stress all right if you ever right we're under a very stressful situation you may start his sweat a little bit okay heat obviously okay because it to cool this down now eccrine sweat glands again in the most numerous and they produce the true sweat right now in terms of the structure of a nekron sweat gland it is a coiled okay simple tubular Glenn okay so let's break that down simple means that the duct isn't branched right tubular means that we're looking at a secretory unit that's shaped like a tube all right so this would this one that I drew over here would be simple alveolar a simple tubular okay will look something more like this all right what we're looking at right an unbranched duct so if I if I use these these cells again to highlight the cells that make up the duct of our gland all right and then we have these cells here all right that what we consider part of our secretory so instead of looking at grape right this type of duct okay it's simple okay here we see the Secretariat looking like a - now this is what our eccrine sweat glands look like but would we do well it's a coiled simple tubular okay so we're gonna take this actually alright and we're gonna now write coil it and look something more like this basically more like kind of like a snake in in a basket for example alright so here we see okay that coiled aspect okay so we say could take a simple tubular gland with called it okay and then there's a duct that leads then to the surface of our skin alright and that produces true sweat the eccrine sweat glands numerous right now a pro cream sweat glands right they're not as numerous and you do not find it throughout your entire body okay you kind of find them very sensitive places you find it in your armpits alright you find them okay in your anal region you find them in your general areas alright and this hasn't produced true sweat it produces a special kind of sweat right their larger size and the special sweat a is typically right kind of a milky or yellow color and consisting of fatty substances and proteins okay and when it's first produced it doesn't smell like anything it's odorless right now these fats though and these proteins it can be broken down and metabolized by bacteria so if this apocrine type of special sweat okay remains on your body for longer periods of time hey what's gonna happen eventually is the bacteria you're gonna start to break these down they're gonna just they're gonna decompose this special sweat okay and as that bacteria okay breaks down that special sweat it's gonna start producing gases and those gases okay correspond to Bo it's a body order so the reason why we want to bathe the reason why we were deodorant right is to then mask or hide okay or get rid of right that special sweat we don't want that accumulating on our body because eventually it's gonna start to smoke all right now if it doesn't really function guys okay to cool us down okay what's the function then of the special sweat what's the function of an apocrine gland right well here are some hints right apocrine glands okay they start to function at puberty all right when sex hormones are released and they get bigger they enlarge they get smaller they recede right with the different phases of a woman's menstrual cycle right so when she's fertile right these apocrine glands enlarge and produce a lot of special sweat okay when she's not fertile right they get smaller all right and they produce a little amounts of special sweat hey their activity okay increases with foreplay so putting all these together and what people believe these applicant glands are used for okay is their analogous the sexual scent glands of other animals all right so when a dog is smelling another dog or a dog can sense that okay another dogs in heat for example right that's what they believe these a protein glands are analogous to in human beings okay all right so the next okay appendage of the skin that we're gonna discuss right our hairs and hair follicles okay so these are some things that we actually touched upon already in lab right so here all right we see skin right we look for a wavy boundary so we know above the wavy boundary again right is our epidermis which is a stratified it keratinized stratified squamous epithelium right below that wavy boundary to part where I actually see the hypodermis okay we call them that our dermis is again is connective tissue it's areolar okay in that okay papillary layer it's more okay dense irregular down here in the reticular layer so we see this imaginary here well this is a hair follicle okay and growing inside that hair follicle our hairs these long filaments that project okay above the surface of the skin so going back to that picture of a human and a mammal like a lion for example okay we don't have as much hair or fur than other mammals okay so again that that led to a reduction in hair eNOS and humans now our hair right in some places are very similar today to the hair you see on a line for example the hair on our heads right keep us warm on the cold days okay prevent then our skin from being hit from direct sunlight on the hot base that keeps us cool now other parts our body though we do have hair but it's not as thick as on the top of our head like if you look at your forum maybe ok yeah very fine hairs alright so is that hair really there to keep us warm is that hair to shade our skin from direct sunlight probably not so for humans what is the function of hair well the main function is more of a sensory role okay to sense things that lightly touch our skin right so if you ever had an aunt for example crawling on your arm okay and maybe he might have been crawling there for like two minutes but and you didn't actually notice it until what until that aunt brushed up against a hair on your form then you look down like oh wow right there's an ant crawling on me and you flick it off alright so the reason why we say it's involved in central reception so I look at this picture here right yeah I can see here's a hair follicle and here's the hair growing out of that okay and here in yellow what do you think these these yellow things that are wrapped around the hair follicle well those yellow things wrapped around the hair follicle well those are a sensory nerve endings right so if an aunt rubs up against the hair it caused the hair follicle to move which then is then okay sensed by these receptors okay which then sends information to your brain you look at your arm like oh there's a nap there okay alright so again the hair on the scalp is more like the frontal line okay protects a head against direct sunlight okay and then he again prevents heat loss on cold days now what about the okay hairs on your eyelash on your eyes eyelids your eyelashes what do they do well when one responds I always get right when when I'm asking my students in person on campus right it's like Oprah take a it's involved in in filtering things from preventing things from from reaching your eyes like filtery really your eyelashes right they're not they're not up there okay trying to like swap things away is it gets coach and coach eater corneas know the function for eyelashes is this okay to sense things that lightly touch your skin so if something brushes up against an eyelash what's gonna automatically happen you can't stop it from happening well you're gonna Blake okay you're gonna close your eyelids preventing whatever that thing that is so close to your eyes from actually touching and damaging your eyes touching and damaging your cornea all right now other hairs like nose hairs yes more like filtering okay the air that the hair is in your ear that's for filtering okay filtering large things from entering an ear filtering large things particles from entering your nose for example okay now hair itself is composed of okay well let me get this first when you think of your hair guys think of you know our skin okay think of the stratum basale okay and then the epidermis the stratum spinosum stratum granulosum stratum lucidum stratum corneum right it's gonna be kind of a modification of that basically so the hair is composed of dead keratin ourselves much like your okay stratum lucidum okay and your stratum corneum is composed of dead keratinized cells now the keratin we see in our epidermis right is more like a soft keratin alright the hair that we see in our hair the hair that we know that hair wants make the keratin that I see it in our hair the keratin that that I see in our nails that we'll talk about next okay that is a type of what we call hard keratin alright so we have soft keratin inner epidermis we have hard keratin in our hairs and our nails well what's the difference well hard keratin is tougher than soft keratin it's more durable alright so if you scratched your epidermis what's happening right now well the cells flaking off okay they're so small you can't really see them but they're coming off of your epidermis okay but you scratch your hair okay you kind of okay rub on your nails okay are those cells rubbing off no they're not rubbing off so by having a harder keratin okay the cells of your hair and the cells of your nails do not flake off all right so this is an easy slide right if we take hair we're not looking at the hair fall came looking at the hair itself the part of the hair that grows in the hair follicle okay that's embedded within the skin we call that the root of the hair so this would be consider the root okay and the part of the hair here that projects okay above the surface of the skin here we would call this the shaft of the hair okay now here is a cross-section through a hair and hair follicle okay so the hair okay is this kind of pale yellow okay and kind of a white okay outer part that's your hair and then what we see here kind of a purple and pink and blue well this is the hair follicle okay so again this is a cross section here now this is a coronal section okay so we're separating and here from poster you can see again the hair here okay kind of a light pink pale yellow and white okay that's the hair and then in right dark pink pink and blue well this is your hair follicle all right now at the core of your hair we're looking at the hair not the hair follicle okay at the core of our hair yeah we have what's called the medulla all right and in the medulla you're gonna find large cells okay and some air spaces between those large cells and this is our medullary as we go laterally in this case okay the cells become a little bit flatter now right and then we call this region right here and here we call this the cortex right this is our cortex here and then our outermost part of the hair it's a single layer of cells in here it's white okay single layer cells right that kind of holds the medulla and the cortex tightly together we call the single ourselves on the outermost part of your hair what we call that the cortex right and they're not end-to-end okay they do overlap like shingles on a roof all right now when your hair is nice and smooth what do you think that cuticle is nice and flat or kind of popped out well right after you use conditioner right you actually flatten down your cuticle all right so when you feel your hair it feels nice and soft and smooth right okay on a day let's say right you didn't okay put essential oils and conditioner in your hair well those shingles can actually flare up a little bit okay even hair can feel kind of more coarse or more rough okay all right so the shingles but the UH the cuticle right single layer cells here in white okay it keeps in the middle in the cortex tightly packed all right now as your hair gets longer and longer and longer and longer well okay it's it's the very ends of that hair it's um kind of older hair obviously right and that hair at the very end of your long hair isn't subjected to lots of what well lots of combing and brushing and washing and blow drying and hair spraying and gelling and what else can you do - here / me and crimping in okay whatever you can do to positive your hair well the hair at the very end the distal end is the oldest hair right and what can happen to this single layer of cells that are holding okay the cells of the meddle in the cortex tightly packed well after a while you can actually damage the cuticle and then the cells in the med John the cortex and start to fray out okay so here what do we see here when we call these split ends okay so by having the cuticle now damaged okay the cells then of the mesh in the cortex they begin to flare out like that okay so the cuticle provides strength and keeps the inner layers okay tightly compacted so that you don't get to put it all right now when we think of our hair it's colored right we have different types of colored hair we have black hair and brown hair and red hair and blonde hair right and different variants of those different types of shades of color now what makes hair colored is is monocytes right so if we look at this coronal section you can see at the base of the hair are these star shaped cells colored and brown well these are melano sites and we know that melano sites do what will they make a brown black pigment called melanin right well these okay Milano sites in addition to making a blonde bright I mean black brown pigment they also make a yellow rust pigment okay it's a combination of these two different shades of melanin hey that then produces all the different contacts a hair color black color hair color brown red alright and blonde right and then what we do we'll then we transfer them to these keratinocytes right we transfer them to the Cerro the hair cells here okay that make up your hair all right so sometimes we see some of our hairs getting gray some of our cells get white right well what's what's happening there okay so if I go back to this picture are we are we producing more melanin or less melanin if you start having white hairs or gray hairs well obviously then in that case you're producing less melanin alright and that can be due to different things can you due to stress okay and when people stress out sometimes they get gray hairs right okay because we could be getting older okay and the older you get what typically tends to happen is you decrease the production of melanin right so instead of okay passing melanin off to the keratinocytes in your hair okay you basically pass nothing right you pass colorless air bubbles right to the surrounding keratinocytes all right so we're gonna now transition from the hair itself now to what grows there and that's gonna be the hair follicles all right so the hair follicles again are tubular imaginations of the epidermis on top of that though they are surrounded by dermis so part of the hair follicle okay you have some epidermis and then surrounding that hair follicle you have some right so you have a hair bulb and you have something called a root plexus right so here you can see the hair bulb okay this invagination Dave and surrounding it here in kind of this purple color well then that would be connective tissue alright so let me see if I can find a picture that shows a complete hair bulb and what we call a hair plexus alright so here we go okay here is a hair bulb okay and inside there is growing the hair and then that that root plexus again we talked about are these branches of okay hair follicle receptors okay so what was the main function of hair right in humans well it's the sense things that lightly touch our skin okay and the reason for that is because we do have okay this root plexus here hey these hair follicle receptors that can sense then movement of the hair follicle all right now the wall of the hair follicle we're gonna look at this coronal section again so the hair is white and everything inside pink and yellow okay so this is our hair everything else that you see outside here well this is our hair follicle right so this first part here is called the internal epithelial root sheet right so this must be derived from the imagination of the epithet okay outside of that is pink what we call this the external epithelial root sheet okay same deal this must be derived from that invagination of the epithet okay and now here in purple what we call this the connective tissue root sheet alright so the outer wall the hair follicle is actually composed of the dermis so this is from the epidermis okay the outer connected tissue root sheet well this one here I'm showing you the connective tissue a sheet it is derived from the dermis alright okay so this next one appendage of the skin alright it's very closely associate with the hair follicle it's something we did discuss already in lab right and we can see it here it's it's it's basically smooth muscle okay it extends from right the superficial regions of the dermis and it just to the hair follicle right and this right here is what we call the erector pili muscle again it's smooth muscles which means what do we have voluntary control over this or do we have involuntary control well the fact that it's smooth muscle okay well this means that we have no voluntary control this is involuntary control so think of in your lifetime okay when okay these would work so right now okay you can see here's my hair follicle okay and when hairs are relaxed okay they're actually at an angle they're not standing straight up like a tree for example they're actually tilted in that angle okay and you've actually experiences probably before okay when you were shaving some part of your body right with a razor so if I were to draw okay just kind of a rough sketch here right so this if this was the surface of your skin for example right and you have these hairs right and these hairs are lying at an angle alright and if you ever shaved okay and you ran the blade in one direction versus the other directions if I if I ran the blade for example in this direction well it would probably feel rough cuz I'm going against the grain right as opposed to what okay well what if I shaved and I now ran my razor blade in the direction of the hairs well then it probably felt a little bit more smooth okay as you were then shaving either your face or your legs all right so when hairs are relaxed okay they are at an angle alright so below that again right you have again these hair follicles okay and the hair follicles are what's growing the hair alright if you want you can even actually put the hairs okay inside of those now when in your lifetime okay have your hairs stood straight up okay meaning that these are rector pili muscles which are connected to the hair follicles contract contract limitate contract is a shortening length causing what then well we're gonna then pull okay we're gonna pull these these hair follicles right in that direction okay and when you pull these hair follicles in that direction essentially you're gonna cause then the hairs to stand straight up okay so here you see our hair follicles are now or more vertical right and then the hairs growing the side of them okay or more like this now so when your life have your hairs stood up straight well one it could be one you're cold alright when you had the chills for example okay or two is when you were scared of something alright so those are the two times that these erector pili muscles actually would contract causing your hairs to stand up when you're cold and when you're scared all right so let's tackle the scared part first right this is not mainly much so much for humans because we don't have enough hair for this to happen but think of about a cat for example alright you've always seen these like decades-- Halloween decorations at the 99-cent store okay or Dollar Tree for example and you see hair standing straight up on the cat right it's freaking out so for other animals that have more hair it's it's used for protection when they're scared why well by having their hairs stand up straight it's gonna make that cat look bigger alright and so whatever okay it's afraid of me now back off saying whoa you know that cat was a little tiny before now it just basically increased it doubled in size for example okay I'm not gonna eat the cat anymore so that's why okay our hair stand out the case kind of this idea of protection making us look bigger okay you're not gonna walk down a dark alley here okay a bottle get kicked behind a dumpster and then all of a sudden you look like the Hulk right you're still gonna look any small so not so much for protection for us it's it's really thermal regulation okay to keep us warm on a cold day so how exactly does making your hair stand straight up okay keep you warm on a cold day well when your hairs are at an angle I can't like this okay they go out your body and they just basically fall flat right so I'm gonna drop just more hairs in the ones that I drew here but when your hairs are long they come out and they just fall flat like on this on the top of your head now when your hair stands straight up okay they go up first then they fall flat okay they grow out and then fall flat they grow out and they fall flat and they grow out and then they fall flat so what you create here is this little space okay between the surface of your body okay and that canopy of hair above here okay so what can happen now to this okay basically this is a space okay containing right air well what could happen to the air in this space now we're over here right heat is being released from your body okay it's gonna go right through the hair okay okay there's really nothing to warm up here here okay yes he's gonna go right through your body okay but what hey this air that's present in this little strapped space now gets warmed up okay we start to warm this air so what we have now is a thin layer okay of warm air get close to the surface of our body okay and by warming air and trapping that air close to serves our body it then keeps us warm on a cold day okay so that's really the function for the rector kalaiy muscles in humans all right for us it creates an insulating layer of warm air trap to the surface okay or close to the surface of our skin all right the next accessory okay organ all right when we think about the integumentary system our Neil's all right so I've been using this figure for like the last 12 13 years now right when I first put it on I just like okay I just googled nails and found an image and it put it on my lecture right after taught I've learned these are a certain type of style we okay well one they're not real these were acrylics now I thought they were real but and I was educated too we call this a French tip okay now a nail is a what no it's part of your skin okay it's a scale like modification of your epidermis okay so again think about your epidermis is above the waiver boundary all right the single layer cells closes we call that the stratum basale lots of mitosis okay the stem cells are there right and we go up will we have the stratum spinosum okay multiple layers cells right there's some mitosis that occurs there is we get a little higher cells get a little flat and squamous okay and then we get to the granulosa that one has the granules and they secrete okay a waterproofing glycolipid right and they secrete a glue that's gonna make carotene in the higher strata and then we have the lucidum and then we have the corneum paying those cells are dead it's like that basically a scale like modification okay of your epidermis now instead of mainly being made of soft keratin like your dermis it's more like your hair it's made up of hard keratin so the cells of your nails again do not flake off all right so if I look now okay at a nail okay we see the distal free edges the part if you don't like your nails long you would clip this part we call this the free edge of the nail okay and then we have the part that looks pink we call that the body of the nail okay and the part of its white also right and then we have this part right here that's not visible okay we call this the root of the nail this is where the nail grows from it grows from what we call this nail matrix all right now the nail which is in white this is a sagittal section now guys we can see a phalanges there okay so here is the white nail on top okay again the nail is a scale lock modification right of okay the more superficial layers of the epidermis so the nail is more like a the stratum lucidum in the shadow McCarney okay deep to the nail in in pink this is the nail bed okay and the nail bed gate corresponds to the deeper portions of the epidermis like the granulosa and the spinosum and the basal okay now below that well then here is connective tissue this is more like the dermis basically you see the blood vessels okay that are present down here in the connective tissue alright so the nail bed is more kind of the deeper layers of your epidermis like the basal spinosum and granulosa okay and then the nail itself right that grows on top of the nail bed these are more traditionally like again the lucidum and the cornea okay now if you look at your nails look at them right now okay they look pink okay and that pink color is due to what well it's due to the blood vessels down here right in the underlying connective tissue okay we already know that well one of the pigments when we think about okay our skin tone okay one of the pigments is what well it's hemoglobin all right so hemoglobin when it's oxygenated when it's violet oxygen has a very bright crimson red and that bright crimson red shines through okay and it makes our nails look pink all right now at the root of our nail over here okay is the nail matrix right and this nail matrix is what actively grows the nail right so if you ever drop something if you ever smashed your finger right if you smashed it right here okay you're gonna damage the blood vessels okay you're gonna see lots of blood pulling it's gonna turn black right here okay now eventually what's gonna happen though you're gonna grow your nail on that that part of the nail this black is gonna go out and grab you're gonna you're gonna cut it with your nail cutters eventually it's gonna it's gonna go away right now if you were to smash your finger or thumb here at the real the nail matrix though okay this region right here well what's gonna happen eventually is you're gonna kind of stall this growth of nail from occurring and this nail will probably fall out first it'll fall out and then a new nail will then follow it okay okay now as we get towards right the nail matrix okay it's so thick okay the nail bed right here is so thick II actually it's white this reason why there's it's white right there it's because okay the matrix is so thick in this proximal region here that the blood vessels containing okay blood and hemoglobin okay it does not shine through okay it's so thick that it appears white basically all right and that white portion there we call this the lenola okay and the Lulla Lulla means the little right okay coming off the sides here and here we call these the nail folds okay and the proximal side here we call this your cuticle okay so we're going to talk about now are things that can go wrong with your skin all right now one thing that could go wrong would be skin cancer right and we need to talk about cancer when we did chapter 2 when we did talk about mitosis okay so we know again that okay to kind of prevent skin cancer from happening right the melanin clusters on the superficial side of the keratinocytes perverting providing an umbrella right and that Brella okay can now shield the nuclei of the keratinocytes and therefore the DNA from the barrage of incoming UV light right which can cause mutations in the DNA all right if you knock out a gene volume for example involved in cell cycle it could be either the promotion of cell cycle or it could be in the inhibition of the cell cycle okay you may cause okay uncontrolled cell division you may cause cancer right in your skin so that's one okay disorder and we did talk about this we're not gonna talk about cancer again when we talk about skin okay another type of disorder though is or our burns right so when you hear the word burn everyone always thinks of fire they always think of heat as something that can burn your skin right well a burn by definition is is basically tissue damage okay inflicted by what not just he but electricity have an electrical burn right you can have extreme radiation you have a radiation burn Hey imagine sliding down the rope during gym class all right because you couldn't get gripped with your feet in your legs okay and there's holding on tight to the rope with your hands well that's gonna be extreme friction burn yeah you put some acids on your hand or some type of base for example some harmful chemical well you can have a chemical burn so burns aren't necessary just by fire heat it could be anything that causes now the damage okay - to your skin in this case now the media threat okay from burns is the loss of water body fluids right so if I think about the dermis that's underneath our skin again right we think about something that has body fluids we think about things that have has blood right so someone gets burned hey you talk about a loss of water and salts all right and that can lead to shock basically right circulatory shock not having enough fluids in your body in addition to that now you don't have that that stratified squamous epithelia dermis right protecting right your body from the outside world all those microorganisms that are out there now can have free reign and get into your body so okay infection becomes okay a threat when we think about a burns to our skin now we're gonna classify burns about how okay based upon how bad they are right and we rate and how bad they are based about about how deep their burn is right how many layers of the skin to be effect or do we go throughout through the entire skin possibly so the first two we're gonna call partial thickness burns meaning that we're not gonna burn throughout the entire thickness of the skin so remember this the skin is what well above the way the boundary is the epidermis stratified squamous keratinized okay and then below the wavy boundary okay again not including hypodermis we have then the dermis so the first two they don't burn through all of that okay the least severe is our first degree burn okay only the epidermis is damaged so here you can see the wavy boundary okay so there's the wavy boundary and then the severe or the thing the burn right here is not that thick okay so we only damaged actually the epidermis okay so we call this a first-degree burn now going to this figure here here's our wavy boundary right there okay but look we went past the way we battery okay so we're actually burning throughout the entire layer of your epidermis we're burning through a portion of the dermis okay so we call this a second-degree burn okay now here's a third-degree burn we call this a full thickness burn so why is this called a full thickness burn here you can see the way your boundary okay and this burn burned throughout the entire epidermis it burned through the entire dermis and now we're actually burning through the hypodermis again which is not part of the skin okay and we're almost okay basically I mean I probably did damage some muscles down here okay so first degree burn second degree burn third degree burn all right so for third-degree burns typically to repair that you can have to take skin from one part of your body and then graft it on to the region of the burnt to help repair that to replace the skin that was damaged in that region there all right so hospitals for example like cedars-sinai they have AI are kind of known in some cases for a their okay burn centers okay so that is the conclusion guys of all right the second portion of the integumentary system Paquette all right and we'll continue on with the next packet and I'll see you guys there and have a good day all right