okay you guys have been requesting a video on the tissues so ask if you shall receive we're going to go through and we'll do this in two different sections we'll do a video on epithelial tissue and then we'll do a video on connective tissue and then just kind of finish up with muscular tissue and nervous tissue the tissue component is typically nice covered in the lab but it's kind of lecture material as well like part of this I'll go through slides and explanations and then we'll look at pictures of the tissue and the reason for that is that I want you guys to learn to analyze the tissue you can't just look at a picture and recognize what it is you can't because different pictures look different depending on whether that's a purchase you it's coming from and might look different depending on what stain you use it might look different so you need to learn how to look at the picture and analyze it to figure out if it's epithelial what kind if it's connective what kind if it's muscle what kind so we'll do that I'll teach you guys how to analyze it we'll look at pictures up here and now I'll show you pictures the actual lab manual as well because your professor may pull up something on the microscope they might show you a picture from Google they might show you a picture from your lab manual you never really know so usually be able to analyze it regardless of where the picture is coming from so we have four key types of tissue um we're gonna start thinking by talking about epithelial tissue the second video will do connective tissue muscular tissue and nervous tissue epithelial tissue is a lining tissue so this is the tissue that lines an open surface so on the surface of your skin this is epithelial tissue lining inside your mouth that's a pretty little tissue inside the vagina that's a peculiar tissue lining inside a blood vessel that's an open area so that's epithelial tissue lining your bladder at the dilly-o tissue they any open surface is lined with epithelial tissue has a few key characteristics one it has a high degree of cellularity that means it's got a bunch of cells the cells are jam-packed together right up against each other so you'll see like cell so cell right next to each other not a lot of extracellular matrix there's not a lot outside the cells because everything is just cells or you'll see other cells might be flat but you'll see them layered on top of each other one after the next after the next again this be kind of epithelial tissue with a barrier it wouldn't be here you could bury her if you had like a cell here and then itself here and they're still here all scattered stuff would seep out of you you need the cells to be jam-packed to really closely together if they're going to be a good barrier so a high degree of cellularity epithelial tissue also displays something called polarity like two different poles right two different sides that just means that one side of the tissue is very different from what's on the other side of the tissue again because it lines an open surface so like this kid for example and we look at your skin it looks like this there's lots of layers of cells right and the very bottom there's this membrane called a basement membrane and the basement membrane is what connects it to the Pantages you underneath okay so this is the epithelial tissue appear down here we have connective tissue supporting it they're connected to each other by this basement membrane okay so this is tissue underneath this surface is called the basal surface so basal is like the bottom surface for the deep surface now we said it lines in open space so that the department's will continue the other side we have the female tissue is lining an open surface so it's completely different right it's open so up here on top the surface this is the air I think that's an open area that surface is called the apical surface so the apical surface is that top surface that's lining an open area the basal service is the bottom of the epithelial tissue where the basement membrane and all these proteins and connective fibers that connect it to the connective tissue underneath epithelial tissue is innervated but a vascular innervated means it has nerves right I can feel this I can feel it if I put something super hot there I can feel that too I can feel a pinch I can feel pain I can said I'll texture I have nerves we do not have a blood supply hey so these veins these vessels that you see those are underneath the epithelial tissue those are down deeper in the connective tissue below or even below that sometimes the epithelial tissue does not have a direct blood supply it does not have muscles in it which makes sense if I have vessels right on the surface any little scratch would make me bleed out I need them to be down deeper so that they don't get damaged or protected when they're down deeper so that's a cap epithelial tissue now when we mean epithelial tissue we name it based on how many layers of cells there are and what the shape of the cell is now right off the bat what I tell you guys is when you're looking at a picture of tissue which will see ducts the first thing you want to do is figure out is it epithelial tissue or is it connective tissue like generally what am I looking at if you see an open area it's a feeling of tissue so if you see a huge white blank space or like a perfect white circle where there's nothing all right like a nice open Moumen epithelial tissue you have to see an open space so if I know it's up at the illegal tissue then the next two things I say how many layers themselves work straight for thing if there's one layer of cells in the epithelial tissue we say that it's simple simple means one layer so here this is the basal surface on the bottom this is the apical surface on the top this is all open right that's all three nothing is there so you look 1:01 sell myself right they're not stacked there's one layer let me say it's simple stratify means there's stratified means there's multiple layers so if you look here this is the epithelial tissue this is the basal surface on the bottom this is the apical surface that's by the free open area that's lining the outside look there's one two three four five there's layers of cells on top of each other so that is sharkbite the next thing we need to look at is the shape of the cellar and the sepals could come in three different shapes when we're looking at the shape of the cell we look at the shape of the surface cells as you'll see sometimes when it's stratified when there's multiple layers of cells this cells will kind of change shape as they go up towards the top so we're gonna name it based on the cells at the top not the bottom okay we'll just see that a couple times cells are either squamous columnar or cuboidal squamous cells are flat selves hey they're perfectly flat when you look at them from the side they look kind of like Fridays because they're so thin that they kind of whoa that's weird they kind of swell where the nucleus is so we get bigger than they get flat again like a fried egg does it from a side so this is the nucleus and they're really long kind of flat fish shells throw other squamous from the top they look kind of like tiles and look when you look down at them from the top you just see their flat shape like that with columnar like columns they're rectangles they're long and thin and stretched out so this is a column in our cell the nucleus is normally down towards the bottom of it sometimes it's more in the middle though a cuboidal cell is cube change okay so it's like a square within your glass right in the center face of cuboidal columnar and scrapes so they'll start with simple squamous epithelial tissue simple means there is one layer of cells squamous means that the cells are going to be really thin and flat and the figlio tissue means it's gonna line some sort of an open space basically this is just a general drawing we'll look at the real pictures in a second but this is all open right these are all big there's a lumen in the open space so there's tissue that's going around the outside of it that's at the fetal tissue lining the open space when you look at this it's one single layer of these long flattened cells races that simple squamous epithelial tissue a single layer of flat cells we see these in a lot of areas we see them in a be old line these are like air sacs in the lungs don't really belong to you but all these tubes that bring air in and then at the end you'll have this little chamber that's alveolus so the air comes in here right and we need the oxygen to go from here and to cross over into the body so we line it with this super super thin layer or one single layer flat cells so that it's a really thin barrier for the air to crossing the body imagine if I had these huge cells here with us it would be really hard for the air to actually cross that vehicle long thick piece of tissue so simple sweetness cells are places where we need to fuse you to occur when you want things to cross the membrane and orally easily a so it allows materials to cross easily so here we see a couple different views of simple squamous epithelial tissue these ones are difficult to analyze the way I normally would because they're from an apical view they're actually looking down with the tissue from the top okay so when you see something that looks like this it looks like tiles with the nucleus in the center right so they're all right up against each other notice there's no space in between them between the cells until you see the plasma membrane in the center of each of them you see the nucleus I think these cells are all packed right up against each other okay this is simple squamous epithelial tissue so there's just give me one layer of cells there but you're looking at it from the top that's why you don't see the open space again it's the only one that's gonna look like these um this is the section of it so you can actually see the open space you can see the lumen so this is all the open space right here this is nothing this is just air right so the tissue that lines the outside of it must be at the Theo tissue when I'm meeting my epithelial tissue the first thing I'm gonna do is say how many layers of cells and then what are their shape so this epithelial tissue it starts right here where these Arabs are it's just this all this underneath is really messy looking stuff that's all different that's connective tissue I'm just looking at this thin layer right here okay so it's one layer of cells right there's one there's one there's one so that means it's simple and the cells are flat right they're not square they're not long columns they're flat so it's pointers simple squamous so the next one that we'll look at is essential I don't know that worked okay so the next type of epithelial tissue is simple cuboidal hey simple means what one layer of cells cuboidal means life with this shut cells are cute Shh right there's square-shaped epithelial means that it's lining and opening area so single layer of cube-shaped cells again remember with these cuboidal cells we see a nucleus nice and centered right in the middle like that so a central round your place we see these in parts of the kidney tubules and then also in some glands the thyroid glands the salivary glands because they're good for secretion so they'll secrete like saliva or they'll secrete the thyroid hormones so looking at them this is the woman and that's the open space so this layer of tissue that surrounds the open space is the epithelial tissue again we've got one layer of cells and they're cute change right there squares with a nice nucleus in the center let's look at the real pictures this one gets henna messy this one's beautiful this one's also beautiful okay so this is the lumen I think this is the lumen that's an open space anytime we have this layer of tissue lining it up in space it must be at the theall tissue I can look at this and this is one layer of cells right there's not styled two stacked on top of each other it's just one cell one layer right next to each other same thing here it's just one layer so that's simple and look at their shape their cube shaped right they're squares with a nucleus knives in the center so simple cuboidal epithelial tissue again you find them in the kidney tubules we find them in some plans okay so we have simple squamous where there was one layer of flat cells we had simple cuboidal where there was one layer of cube shaped cells now we have simple columnar where there was one layer of column shaped cells so simple means there's one lighter columnar means that cells are tall column shaped so they're tall rectangular cells the dampener links is normally kind of toward the bottom part of it but not always sometimes when we look at this tissue will see goblet cells present that said can secrete some mucus but not always um sometimes we'll see Celia present but we'll look at that later when we look at these cells they're really important for absorption and they can be important for the secretion of mucus so we can see them present parts of the GI tract we can see them present in parts of the reproductive tract as well where they've got cilia to the egg along the surface of the cells so both of these are showing us simple columnar epithelial tissue clown this is from the GI tract from the small intestine so this is all open space right that's a lumen it's open and inside the GI tract it's an open to write that food boxes growth so when we look at this open area this open lumen it's layer or covered with a layer of epithelial tissue so from this all the way up this right here is all the epithelial tissue when you look here each one of these rectangles is a cell and this dark area is the nucleus so this is one layer so and each of the cells are these tall thin rectangles there are these long columns so that's simple columnar epithelial tissue this tissue happens to have micro villi on the surface not Celia but micro villi this limps at these tiny little like hair like extensions those are important for absorption they increase the surface area of the cell for absorption which is really important in a small intestine looking here again this surface deep are back with a little tissue this is connective tissue underneath notice how unorganized it is right this is the ethereal tissue lining all this open space these are long thin cells one one of them so that simple columnar epithelial cells may you see the nucleons the dark area this is a goblet so again a goblet cell secretes mucus so we went to create a nice thick protective mucus under the surface of the cells but that's simple columnar hey so now we're going to talk about a couple types of or first we're talking about pseudostratified so we just looked at simple epithelial tissue simple has one layer cells stratified has many layers of cells pseudostratified is like think stratified pseudo means false so it's like it looks like it's stratified it looks like there's a bunch of layers of cells but there's really not every single cell is anchored at the basement membrane every single cell actually touches the bottom touches the basement membrane so they're not actually stacked on top of each so it looks like it's stratified but it's really not so we call it pseudo stratified columnar epithelial tissue again looks multi-layered but it's not the way that you can identify this is that it looks cologne arm there are these really tall cells however the nuclei are not nicely organized you don't see the nucleic nucleus nucleus nucleus all in a row you see the nuclei all scattered at different levels towards the bottom that's how you know it's pseudostratified columnar basically nuclei are all at different levels we see Celia present on a lot of these we find them in the respiratory tract remember the Celia are just little the hair like extensions on the surface that move they do this to push mucus across the surface and that's important to getting your respiratory tract you don't want the mucus to drip down into your lungs so the Celia movement like this up towards your throat and then you talk about the mucus okay so we did a couple different examples now here the tissue starts at this basement membrane and goes up so that is the epithelial tissue this is all open space up here this is connective tissue underneath it's a lot Messier so when you look at this these cells notice how you see the nuclei clustered at all different levels but it's all unlike the bottom okay so like the bottom like two-thirds of the tissue you'll see the nuclei at all different levels so it looks stratified even though it's not based on that pseudo stratified ciliated columnar epithelium still the ages because it has cilia on the surface that picture is really difficult this one's a little bit better so this is all the show renounce the epithelial tissue okay notice here you can kind of see these long column shapes of ourselves okay so we know it's : arm and because the nuclei looks like they're stacked it looks stratified but it is not okay it's pseudo stratified again you can tell because the nuclei are all at different levels on the bottom like this if it was simple columnar then the nuclei would all be in a row like that hey we'll see another interpretation in a second were the new feeling go all the way up to top so those are like the key difference where is the nucleus if the new piece is the bottom two-thirds pseudo stratified ciliated columnar epithelium if the nucleus is straight in the center it's simple columnar epithelium if the nuclei go up to the top we'll see in a minute that's gonna be something called additional okay so now we will look at some different types of tissue where the cells are actually layered on top of each other so this is what we have multiple layers of cells we call that this stratified epithelial tissue the multiple layers of cells provide protection okay so like this skin right here we have a bunch of layers of cells why because it gets damaged all the time right there I'm scratching off tons and tons of cells when you shower when you dry off when you get dressed when you bump into something you're constantly losing cells so you need multiple layers so that you don't end up with ulcerations and holes present thinking in your mouth right you take a bite of food you're chewing or swallowing a chip you scratch away at that tissue the vagina the anus same thing we need multiple layers of cells to provide protection sometimes real keratinized those cells that just means we add a bunch of keratin keratin is what makes your skin strong what makes your hair strong what makes your nails strong keratin is also water-resistant so that's why like our skin you can put your hand in water and you don't automatically fill with water or why our insides don't just seep out of us because this this layer on the outside of her body is keratinized so it provides water resistance or water protection as well again we already mentioned this but when we're signing the cell shape we will be the cells at the top right in the apical layer so we only look at stratified squamous epithelial tissue and you guys should be able to identify keratinized stratified squamous epithelial tissue and non-keratinized stratified squamous epithelial tissue hey this sounds like a lot but it's really not you should be able to analyze what we're talking about based on the name at the field tissue we're lining an open area right the mouths were lining the vagina lining that the skin something stratified we've got a bunch of layers of cells squamous the cells on the top are thin and flat they're not thick swears they're not tall columns they're thinning flat that's it character nice we see a ton of dead keratin on top not on Carolinas we don't see that dead care to show each other thanks to it sounded like a ton like it's really hard but every word tells you something again multiple layers of cells provide protection the cells become more flat as they go towards the surface keratin race means we just have the dead keratin packed stuff on the top non-keratinized means we don't so the keratinized stratified squamous we see in our epidermis that's the top layer of your skin price you were moving your kids like did you ever say the joke hey your epidermis is showing like yeah everyone's epidermis is showing like this is your epidermis maybe outer layer of your skin that's keratinized you had this big dead skin on the top right these dead skin cells it's dry that keratin provides water protection water resistance this is moist all the time non-keratinized stratified squamous epithelial tissue lying on the open areas that are wet so your oral mucosa key lining inside your mouth inside the vagina inside the anus these are all moist membranes they're still stratified because they need protection but they're not characterized they don't have that water resistance because we want them to be moist we release a lot of moisture on those areas so let's look at them these are both stratified squamous epithelial tissue disorders keratinized this one is non-keratinized okay so let's look at it the tissue is going from the curvy line up so this to this back a filial tissue this is all open so that's lining this open space that's outside the body stinking here it's from this kind of curvy line that's the epithelial tissue these so this is elevated by you this would be like in the mouth with the esophagus or something so let me look at this one it's from the curb you line up its epithelial tissue cancers line in this big open space it's stratified because I have numerous layers of cells this might be kind of hard for you guys to see because it's small but there's like all these dark spots are showing you nuclei okay so there's numerous layers of cells you can have a hundreds of layers of cells here this cells are really flat they kind of tell just by how jam-packed close they are together it ever nice big squares you would see them if there were these tall rectangles you would very obviously see them they're relatively flat cells so they're squares so stratified squamous epithelial tissue this is keratinized because this see all of this you don't really see anything right it's just bland jump there's no nuclei left the nucleus has disintegrated it's literally just sacks of interconnected keratin so it just looks like a sheep of this dead skin cells of keratin so this is keratinized because that layer look over there you don't see it okay so here this is the epithelial tissue because it's lining an open surface it's stratified look at these nuclei you can see there are layers upon layers layers of cells right so stratified and themselves are flat okay when you look at them I mean they're flat little cells you don't feel like a nice square of a cell membrane so stratified squamous epithelial tissue it's non-keratinized cuz look the cells go all the way up to the top there's not a thick layer of just dead keratin on that so that is non-keratinized so in your mouth your vagina your anus top against the last type of epithelial tissue that we'll talk about its transitional epithelial tissue this was kind of weird we name it differently than all the others it's transitional epithelial tissue because it's always in the state of transition so it looks different depending on what's going on we see transitional epithelial tissue lining areas that change size and shape align and areas where we have to protect from osmotic damage so we have to protect from all the solutes in the fluid transitional epithelium is very classically found in the bladder we also find it in that your readers though urethra those are the tubes that carry fluid to the bladder and then out of the bladder and out of the body but the bladder is kind of the plastic answer here for where we see transitional epithelial tissue and the bladder obviously as it fills up with urine its strictest right in an after you pee it drinks so that tissue is always you straight of trans and a state of transition its transitional the tissue can get really thin and flat as you stretch it and then when shrinks back down can get kind of thickened from the again so it's always in a state of transition but the way you identify this is there are multiple layers of cells the nuclei go all the way into the top the top cells are typically a little bit rounded here so let's look at this is what it looks like I know that this is apathy illegal tissue why there's all this open space lining a big open spaces epithelial tissue okay so this Center here is really weird and disorganized right so this is all connective tissue but this tightly packed tissue from here all the way up to here this is all epithelial tissue okay so epithelial tissue I'm gonna look at this and say okay look here my cells I see you know I obviously have a lot of layers of cells the nuclei are going all the way to the top and the top cells are kind of rounded that's transitional up a few little tissue in the bladder okay now you might confuse this with pseudo stratified epithelial tissue but remember which pseudo stratified epithelial tissue the nuclei were scattered throughout like the bottom two-thirds of the tissue the nuclei did not go all the way up to the top also you saw little cilia on the surface you don't see those Celia present here right then you didn't see these rounded surface cells also it's not I mean like if you look at this stratified squamous oops if you look at this stratified squamous right here look these cells are a lot flatter you don't see that nice big round cells think so the transitional has those really round cells up top the way that I would recommend you guys learning these is of course to go through them and learn how to analyze them but then find one that you'll easily mix up with each other and figure out how to distinguish them from each other okay so look at the simple columnar in pseudostratified columnar make sure you can tell the difference look at pseudostratified columnar and transitional make sure you can tell the difference look at the stratified squamous non-parents now as you characterized make sure you can tell the difference okay put all of those things right up like test yourself right now otherwise if you don't do that when you get to the test you're gonna panic and you're not going to tell the difference between them raise them analyze them confuse yourself now pictures right next to each other and figure out how you're gonna know which one is which okay and remember the simple squamous tissue the one layer of flat cells when you look at it from the top it looks like tiles okay and it has a nuclei in the middle so it looks like you've got these cells like this and you have a nucleus in the middle in connective tissue we're gonna look at adipose of course tissue is going to look very very similar to the simple squamous but there's no nucleus for the little baby so that's here to tell the difference if it has a nucleus in the middle it's simple squamous epithelial tissue if it's just these fat cells with no nucleus in the middle that's adipose tissue okay so we'll talk about that works you are very welcome to this