hello and welcome let's talk today about tissues basic we're going to get into the histology aspect of this class now here this introduction to the histology now is going to be basically taking us into tissues and a study of tissues so here when we talk tissues tissues are basically a living fabric is one way to kind of think of it now when we go through when we talk tissues tissues we talked about in the previous chapter are groups of cells groups of cells that are going to be similar in structure and perform a common or related function and we also mentioned the four primary tissue types where basically we said our body gets broken down into one of these four primary tissue types so you break your body's components down skin connective tissue we're going to see it's going to be we've got to get our when we talk primary tissue types here we've got first let's mention those and we'll basically check out how everything gets broken down skin will see this connective tissue and it's going to be made up of epithelial tissue as well and we'll go through we'll talk again so we talk primary tissue types we said are four so epithelial number one we saw epithelial as being a lining tissue and then number two we said connective tissue connective tissue does more than connect we'll see most of the providing support muscle tissue we said movement and the nervous tissue allowing for internal communication okay internal communication with the internal aspect and also with basically the external components of the body and allowing information to make its way to the CNS and then back from the CNS now when we go through we talk tissues so tissues our body gets broken down into one of these four tissue types okay and we'll go through we'll see all of them starting with epithelial tissue first we'll tear apart epithelial tissue then we'll jump to connective tissue tear it apart and do muscle tissue tarry completely apart and I will do the same thing with our nervous tissue and tear and nervous tissue completely apart as well so let's start with epithelial tissue epithelial tissue is also known as epithelium here this first line is a nice slide of the epithelial component and also some connective tissue we can appreciate underneath here as well of basically you know you'll see the small intestine of the digestive component so here you can see it's epithelium with a small intestine it's showing one certain type of cell here right now it may not look like anything to you but once we've gone through the lecture this will make more sense to you okay and then again here we're going to see a little bit of connective tissue providing its support so when we go to we talk a pictorial tissue epithelial tissue is also known as epithelium epithelium now epithelial tissue or epithelium is a sheet of cells it's a sheet like when you think of a sheet of plywood a sheet for your bed okay so you can think of it as a nice long sheet so it's a sheet of cells that covers a body surface or lines a body cavity now the general forms of epithelial tissue are a couple of types number one epithelial tissue can be found as a covering and lining epithelium okay so tissue we went through we talked tissues we talked to histology and here we broke down all four tissue types you can see the body gets broken down into these four tissue types it's a one good example there and then again those four tissue types so it's important you understand those tissue types you can see how much we've mentioned them again if you took bio 1:07 you've seen these this is all review they're all four tissue types giving you a basic idea again same thing here same thing here now we're going to look at these tissues we're going to study these tissues and they're basically going to be preserved so tissues are going to be fixed and they're preserved now here how are they made they're going to be basically cuts they're going to be cuts of you know you'll see tissues from organs basically that are going to be put on to then slides they're stained and then we're gonna use the microscope to go through and look at them so when you talk preparation preparation includes fixation the actual section what is being cut now when you're making these different cuts you can look at bone a couple of different ways you're looking at bone you're gonna say yeah well here I see a bone bone bone these three images just bone but now this bone can be either cut you can if you remember along the longitudinal section we talked about a couple of longitudinal sections yesterday or in the last chapter chapter one and then here you can see you can have a cross-section of transverse cut cut along the transverse plane or you can have an oblique section now if you were to have a longitudinal section longitudinal section now will look like this if we were to look at the bone further cut here and look at the inside of the bone this is what the inside would look like in there if we were to do that with the blood vessel and here you can see what the blood vessel would look like that we're basically going to be able to look at this end and at this end here so that's one end here and then the other side of the blood vessel now if we're to make a cut along the transverse transverse cross section turn that around this is what the bone would look like so you have to be able to identify bone from here and here like I was telling you guys in class same thing with you know students and kind of what we have going on there now blood vessel here transverse a cross section this is what it'll look like now bleep cut a bleak section this is what the top will look like now here if we got to a blood vessel you can see how that would look so we have various plains of section so reiterating that chapter now same thing with you can see an egg for the cut along well here's a midsagittal here's a parasagittal and here you can see a more laterally placed Paris astral and what are we going to see there we can't see any yoke here we can see some yoke midsagittal we can see yoke and a full contour of that egg almost and then we'll make a cut along this plane again the same thing here same thing we can see with this tube you'll and then the same thing here right nice transverse cut a nice vertical cut vertical plane so epithelial tissue now when we talk a petite issue I said general forms two types first type is covering and lining epithelium now we talk covering and lining epithelium this forms the outer layer of skin it lines the open cavities of the urogenital digestive and respiratory systems and it covers the walls and organs of the closed ventral body cavities that we spoke of in the previous chapter as well chapter one second type then is glandular epithelium glandular epithelium now glandular epithelium forms the glands of the body it forms the various glands and you see is mostly the secretory tissue in our glands now let's go through and let's talk general functions so some general functions we can see our number one protection epithelial cells they protect underlying tissue they protect underlying tissue from mechanical injury from harmful chemical pathogens and excessive water loss dehydration another general function is absorption certain epithelial cells lining the small intestine absorb nutrients from the digestion of food filtration then as a third function filtration now filtration is going to be we'll see a function of the cells in the kidney when we talk about the kidneys each kidney is going to contain cells that will be responsible for filtration excretion excretion is going to be also a function of the cells in the kidneys and also of epithelial cells in our sweat glands excretion they'll be removing from the body not to be confused with secretion secretion glands which are epithelial tissue are going to secrete specific chemical substances such as enzymes hormones and lubricating fluids we talk secretion secretion will see these components are moving from one place of the body to another place of the body six then we can see their sensory reception now we have specialized epithelial cells that are going to detect sensory stimuli now when we go through we talk about epithelial tissue epithelial tissue I'd like you to know has some special characteristics here are some special characteristics we can see number one is that epithelial tissue is going to have polarity we'll go through and we'll talk about each of them and specialized contacts we'll talk about the support that epithelial tissue receives from connective tissue as I've been mentioning now a few times we'll also talk about how epithelial tissue is a vascular however it is innervated and it has the has a regenerative capacity has a high regenerative capacity it can regenerate so let's talk first polarity I would like you to know all epithelial cells have an apical and basal surface is basically what we're saying when we say that epithelial tissue has polarity so cells have polarity and an apical surface and a basal surface the apical surface is the upper or the free surface it's the upper or the free surface it's the surface that is exposed to the body's exterior or to the cavity or so it's a surface that's exposed to the body's exterior or the surface that's exposed to the cavity of an internal organ now this apical surface it can be smooth and slick or it can have a couple of will see modifications there so if we were to look at this row of cells now we're to look at this row of cells you can see here this basically top part of the cells as the apical surface and I like to think of a apical four addict it's in the top okay so if we're talking about let's say this down here now apical surface we can see right up inside of here so again it's a surface that's exposed to the exterior or into the many of an internal organ next then we have the basal surface now the basal surface is the lower for the attached surface so here you can see now the surface right down here basal surface okay so that's what we say when we say epithelial tissue has polarity has two surfaces now when we hoped when we talk about the apical surface I told you the apical surface can be smooth and slick or this apical surface can have micro villi to it or you can have micro villi to it can be smooth and slick or it can have micro villi to it now we talked to micro villi micro villi are going to be finger like extensions they are finger like extensions of the plasma membrane now what they do is they increase the surface area micro villi increase the surface area now in epithelia that absorbed in epithelia that absorb and secrete substances like your intestines and or your tubules of the kidneys micro villi is so dense that the apical cells those apical cells basically surface there is going to have a fuzzy appearance so that micro villi is so dense that the cells apical surfaces the apices have a fuzzy appearance and we refer to that surface there as the brush border the brush border so we talked brush border brush border is going to be the regions of the intestinal lining or we said in the kidney tubules where you have micro villi it's apical surface to be very very dense very dense that we call it brush border it's very important because in the small intestine we're going to have a lot of enzymes there and those enzymes are going to be basically ready to go and break down whatever component makes its way through the digestive tract let's say for example when we talk a lack taste lactase it is a brush border enzyme it's responsible for breaking down lactose which is a mill which is a sugar that we find in milk so correct yeah people don't have it are going to be lactose intolerant because they are lactase deficient so microvilli and now here when we talk micro villi we can see here so micro villi are your finger like extensions of the plasma membrane so here let's say let's go back to this picture I have to draw anything in right inside of here now right inside of here this structure itself okay this structure itself you see here is a villi now the villi has this micro villi right inside of here Seath right inside of here if we were to look at one of these cells now basically here you can see this one villi is made up of a whole bunch of different cells we look at this one cell this is the apical surface of that cell down here this is the basal surface of that cell right we've established that already so here at the apical surface we said it could be smooth and slick or it can have micro villi there so these are the micro villi for the zoom in here okay let's zoom in on basically this whole cell right here this is what it would look like okay and you got the nucleus right and said here's important you know that nucleus a lot of students come to Anatomy and aren't sure about the nucleus which is what you learned from bio and then right on top of here okay here we're going to have basically surface looking like this so if I was gonna zoom in here now this is what that would look like you can see here now what this does is it increases the surface area why would we want to have that surface area increased in digestion we're trying to digest so when we're trying to digest we want to make sure we can absorb everything we need from there okay so that's what that surface looks like there now you can have either this micro villi so micro villi are going to be finger like extensions of the plasma membrane they increase the surface area in epithelia that absorb and secrete substances micro villi we said is so dense that the cell apices have this fuzzy appearance you can see here and we refer to it as brush border we call it brush border if there's no micro villi there we can also have here cilia so that surface can have if there's a micro villi there if it's not smooth and slick we can also have their cilia cilia are tiny hairlike projections tiny hairlike projections that propel substances along their free surface they're found on some epithelia such as epithelia that you find lining the trachea for example your windpipe and now here this is what the cilia will look like now here we've got the cell let's just say and now here these are gonna be tiny hairlike projections now before we said we had micro villi mikrobill are totally different from cilia okay so make sure you fully read and understand the difference here tiny hairlike projections versus we described as finger like extensions of the plasma membrane so they're gonna help to push things along the surface that's when the windpipe when we're breathing all right well I always joke you know if we don't walk around wearing masks lo and behold the third times we're in you know we are wearing masks now I used to joke around my students and say we should apply for a an EPA deductible every year when we fill out taxes saying if we breathe we should get a certain cut because what we're actually doing is we're filtering the air all right by bringing in all the pollutants and everything allowing them to come in here stick in here and then cleaning the air and sending it back out now here the cilia is basically there to help remove particles that may make their way in that we are not able to see and that's the importance of cilia very very important next in here we can see we have specialized contacts so the second characteristic is specialized contacts now we talk specialized contacts we're going to see tight junctions and we will see desmosomes tight junctions and desmosomes what they do is they bind adjacent cells together and help maintain polarity so these contacts are going to be found between adjacent cells and they bind adjacent cells the tight junctions obviously really in a tight fashion we'll go through as a semester president will actually see pictures of each of these as well and then you have other lateral contacts known as desmosomes and then in certain cells we're going to see in between these contacts we will have then what we call basically gap junctions like in relation to cardiac muscle cells next I would like you to know then when we talk a petition is supported by connective tissue epithelial tissue is supported by connective tissue so nosey sitting at home now when we talk supported by connective tissue all epithelial tissue rests upon all epithelial tissue rests upon and is supported by connective tissue now we have here reticular lamina reticular lamina is going to be a layer of extracellular material it's a layer of extracellular material containing a fine network of collagen fibers that belonged to the connective tissue now here we're going to be able to appreciate basal surface we skipped a basal surface so after cilia actually we were supposed to talk about the basal surface so let's jump back up back up to the first characteristic of the apical surface now we skipped the basal surface totally so let's go back basal surface we said is a lower the attach surface so I get for being nosy I guess it's a lower or they attach surface so when you talk and compare the apical versus basal surface both surfaces are going to differ in structure and function obviously because of look at what they have apical surface if it has micro villi it's gonna be involved with absorption there right and if we're talking cilia it's gonna be of all the moving things along now the basal surface is the attached surface so here what we have at the basal surface you can see is going to be now basically basal lamina now basal lamina is a non cellular then supporting sheet of collagen I'm sorry collagen fibers and glycoproteins it's a thin support sheet of glycoproteins and collagen fibers and it's found lying adjacent to the basal surface it's found lying adjacent to the basal surface and it's an adhesive sheet it acts as a selective filter it acts as a selective filter and it determines which molecules can cross from the connective tissue up into the epithelial tissue which molecules can cross from the epithelial tissue from the connective tissue up into the epithelial tissue so now we've taken care of that apical and the basal surfaces so they become surfaces up here this is where you can have the cilia or you can have micro villi here down here is where you find that basal surface and where you find the basal lamina okay same thing right down in here basal surface where you find the basal lamina so basal surface I think of basement attic at the top of the house and then basement then specialized contacts right we took care of now the third characteristic I was telling you guys about now is that epithelial tissue is going to be supported by connective tissue now all epithelial tissue rests and is supported is resting upon and is supported by connective tissue now here we have our reticular lamina the reticular lamina is a layer of extracellular material it's a layer of extracellular material that's going to contain a fine network of collagen fibers that are going to belong to the connective tissue that will belong to the connective tissue so you've got basal lamina and the deep to the basal lamina the reticular lamina now now when we talk basement membrane basement membrane is formed from the two laminae so when we consider the two laminae the basil lemon and the reticular lamina we refer to that as the basement membrane basic memories gonna be important when we get to the kidneys for you to know now the basement membrane what it does it reinforces the epithelial sheet it also helps it to resist stretching and tearing and helps it to resist stretching and tearing and it basically defines the epithelial boundary there so everything above there is going to be epithelial tissue and below it connective tissue next we said epithelial tissue is a vascular but innervated so we say a vascular we're saying it contains no blood vessels contains no blood vessels so it contains no blood vessels so it's a vascular and it is supplied by nerve fibers it is supplied by nerve fibers if you've ever cut yourself okay so superficial you've seen sometimes it doesn't bleed but with me I'll notice the skin color change I'll notice it goes from being a dark to being light an oak I've cut myself but it wasn't that deep all I did was just cut the epithelial aspect so epithelial tissue is a vascular but innervate it meaning it contains no blood vessels but it is supplied by nerve fibers so if it doesn't have blood vessels it has to be nourished by diffusion from underlying connective tissue next then is regeneration epithelial tissue has a high regenerative capacity it has a high regenerative capacity we see that when we see skin sloughing or if you cut yourself alright you don't walk around with the cut for the rest of your life that'd be horrible and again we're shedding our skin constantly dead skin is falling off so these are all special characteristics in relation to epithelial tissue now when we go through when we talk at Bethulia tissue so all special characteristics now we go through we talk about epithelial tissue all epithelium each epithelium is gonna have two names has two names the first name indicates the number of cell layers the first name is going to indicate the number of cell layers and the second name is going to describe the shape of its cells so we talk at the o2 Shepard is gonna have you'll see at least two names first name is going to describe the number of cell layers and then the second name is going to indicate the shape of the cells so when we go through we talk about covering and lining epithelium will go through general classifications and here we'll generally classify our epithelium according to the number of cell layers first when we classify epithelium according to the number of cell layers we'll see we have two major classifications here your epithelia can be classified as either being simple epithelium now if we're talking simple epithelia simple epithelia is going to be epithelium that is going to be found as just a single cell layer just one cell layer simple epithelium is typically found where absorption secretion and filtration are going to occur right because in those areas you don't want to have a thick layer you want to have just a single cell layer the second classification is stratified epithelium we talk stratified epithelium at stratified epithelium is going to be composed of two or more cell layers two or more cell layers where the cells are stacked on top of each other stratified epithelium stratified epithelium is going to be common in areas of high abrasion in areas that suffer high abrasion so high abrasion areas where protection is important like the skin surface like the skin surface and the mount will say for example we'll learn more as we progress so those areas you want stratified versus just a single layer of cells so the first name is going to be either now we'll see simple epithelium or stratified epithelia let's add the second name instead of epithelia so when we talk second name now the cell shape is what we're going to be looking at here now we talk cell shape we have either squamous cells which are going to be flattened and scale-like cells so whatever it's there another image here squamous cells you can have which are going to be flattened and scale-like cells or you can have cuboidal cells which you can see are box-like cells they are as tall as they are wide columnar cells columnar cells these are tall and column shaped cells column column shaped cells so let's specifically classify that epithelium no weeks specifically classify epithelium we're going to have first simple squamous epithelium okay we'll talk first simple epithelium then we'll take care of stratified epithelia so first simple epithelial you have a simple squamous epithelia when we talk simple squamous epithelia you have to be able to describe it know its functions and locations I can ask you any of that stuff on the exam and you have to be able to answer those questions so when we talk about description simple simple we said one single layer squamous flat squished cells so when we describe simple squamous epithelia you can see it's going to be described as a single layer of land cells with disc shaped central nuclei these cells will have a very sparse cytoplasm and they are the simplest epithelia that you'll see they are the simplest epithelium we'll see now when you talk about the function of simple squamous epithelia simple squamous epithelia it allows for the passage of materials it allows for the passage of materials by diffusion and it's involved with filtration where protection is not important and it's also going to be secreting lubricating substances in our serosa where do you find this type of epithelium this epithelia is going to be found in the glomeruli of the kidneys the kidneys have a region called the glomeruli if you recall from 107 if not here you can see we have basically this structure here if you talk about the kidneys the structural functional unit of the kidneys is going to be called the nephron so here is an image of the nephron now everybody is responsible for knowing about this nephron it's a complete fair game so you could go through and understand all the different parts of this nephron here you have right inside of here a whole bunch of blood vessels and this is where blood comes in to gets filtered whatever needs to be removed gets removed whatever doesn't get removed it's gonna get sent back into your circulation through this blood vessel so this vessel here is the glomeruli when we talk kidney glomeruli is one area where you gonna find it you're also gonna find it in this parietal later we're gonna see I'm sorry here we're gonna see this layer right in here is gonna be found attached basically right on top of this glomeruli okay so here I've kind of exaggerated this difference here okay this is all a test we'll see all together this all makes up your filtration membrane this side here and then this side in here and everything in between now right inside of here this is all going to be we'll see now basically these simple squamous epithelial cells are all out right side of here and then right inside of here because this layer is not that thick and here what's gonna happen is right inside of here as well where filtration will take place okay substances will make their way out in here and right when they're in here they're gonna be passed along into here so one major area where you're gonna find this epithelia is going to be in here but then we progress through we talk the kidneys glomeruli and we get into the nephron we talk the nephron in greater detail we'll talk with Neela and all these other parts there we'll look at these cells and we'll see them right outside of here as well so here you can see then make sure you know that nephron they're also now another area where we're going to see is going to be this image like we're seeing here these are the air sacs inside the lungs inside the lungs you see when we make their way all the way through all the way to the end we have our air sacs now here one side of the air sac you have air the other side is gonna be blood here you had a blood and basically solute membrane here and here we're gonna have blood and air membrane so here why do we not want to have thick layer because we're trying to get gases to move across right diffusion is the word we keep saying diffusion means something you learned it by oh so just that one word is saying a lot okay movement from high to low right and that's exactly what we're gonna be seeing here with oxygen and co2 so air sacs of the lungs lining of the heart lining of your blood vessels the lining of your lymphatic vessels and also your ventral body cavity lining that we saw the cirrhosis a simple squamous epithelium next and we have endothelium when we use the term endothelium endothelium is still simple squamous epithelium now we get cute we get fancy whatever you want to call it in science and we start to give specific things names now endothelium is going to be the specific name for the simple squamous epithelia found lining our lymphatic vessels our blood vessels and our heart so if I was to ask you we're to show you a picture and show you that mining and saying what do you have here you would have to say this is endothelium which is simple squamous epithelium found lining the blood vessel or lymphatic vessel another term is mesothelium I'm sure you've heard mesothelioma on TV mesothelium is going to be again simple squamous epithelium now this is simple squamous epithelium found in relation to our serous membranes the membranes that are lining the ventral body cavity and covering its organs that we discussed in chapter one we call that mesothelioma so you've probably seen these commercials lawyers do you suffer from mesothelioma have you worked in a shipyard or here here here and there helping patients to receive compensation I guess but mesothelium is what's affected so you have to understand then what mesothelioma is okay because it's affecting the mesothelium next let's move and here you can actually appreciate more images of simple squamous september's come back in here here you can actually see one little squished cell right inside of you and then here you can see the nucleus inside in purple and if you look at right next to it another squished cell the nucleus in purple another cell but this nucleus didn't stay in purple it's a slide it's not gonna be picture-perfect sometimes you may not even have a nucleus there and you have to recall and use your information and identify that as whatever cell it is so here you can see all basically just one single layer of cells here you can see the same thing simple squamous epithelium another simple squamous epithelial cell another simple squamous epithelial notice simple squamous epithelial squamous epithelia simple squamous epithelia honest simple squamous simple squamous all connective tissue you underneath here providing support as we mentioned so you can see the apical surface would be right up here and the basal surface would be down there now in mesothelioma in mesothelium and endothelium I'll never ask you to identify apical surface and basal surface because you're looking at the apical surface and we move to the lab I'll show you that in the lab well in that if I show you a picture like this you should be able to identify apical surface and basal surface so again here's the muscle and connective tissue all down here providing support to the epithelium up here so two other locations endothelium and mesothelium let's move them to simple cuboidal epithelium we talk simple cuboidal epithelium again description simple single cell single layer of cube-like cells with large spherical central nuclei the function is secretion and absorption so here you can see some of those cells a nuclei didn't stain here but you can see one cell okay this is a cube right here we set equal height and width so one cube shaped cell here's another one another one another one now the one but no nuclei that's okay here you can see here's another one with nuclei so that's enough for you to understand you have simple cuboidal epithelium same thing here these few didn't stay in that well here's a little light one here you can see very well and then coming all the way around these cells are going to be found in the kidneys tubules the ducks and the secretory portion of our small glands and also the ovary surface and also the ovary surface so the kidney tubules coming back here to the nephron these are the tubules this is one set of tubules proximal convoluted to here's another set distal convoluted tubules here's the loop of Henle another set of tubules so you got to make sure you know all the parts and the collecting ducts at the end this is inside the kidney each of your kidneys have millions of these tiny blood processing units that are called nephrons okay we're going to talk more about them this class is so much fun so here you can see simple cuboidal epithelium next thing we have simple columnar epithelium simple columnar so single layer of tall cells with round two oval nuclei and some of these cells can have cilia and this layer we'll see can also contain goblet cells which are a type of mucous secreting unicellular gland one celled gland called goblet cells and we'll look at those who will check those out as well now the function of these simple columnar epithelia is absorption now if a cilia there we'll see it's helping to move things along absorption secretion secretion of mucus we can see secretion of enzymes and also secretion of other substances now if we talk ciliated type the ciliated type we said is going to be responsible for sending or propelling substances forward now where do we find this type of epithelia so for talking ciliated types ciliated types will see in reproductive cells the uterine tubes more specifically speaking and some regions of the uterus also lining the small bronchi and lining the small bronchi now the non ciliated type the type that does not have cilia the non ciliated type is going to be found lining most of the digestive tract most of the digestive tract from the stomach to the anal canal the gall bladder and then the excretory ducts of some of the glands will have the ciliated type there as well the non ciliated type there so this is all simple columnar epithelium next and let's move to pseudostratified columnar epithelium so simple columnar here we can appreciate some goblet cells three of them again column shaped cells and here they've got some have micro villi to them next it'll look good let's look at these pseudostratified let's move over here pseudostratified columnar epithelium now when we talk pseudo stratified pseudo is the word we want to break down pseudo means fake right stratified so it's a fake stratified meaning it looks like it's stratified but it's not so if you look at this picture you can see it does look stratified but it's not stratified so this cell epithelial cell basically is going to be described as a single layer of cells of differing Heights some cells are taller than others so those cells that are taller than others are going to reach the free surface while others may not know because of that the nuclei are going to be seen at different levels and these cells you can see also sometimes will have mucous secreting cells and sometimes we can also find cilia here as well now when you talk about the function secretion particularly secretion of mucus and then propulsion of mucus thanks to the cilia now when you talk locations so if you have non ciliated pseudostratified columnar epithelium its found in the male's sperm carrying ducts why would you why why do we need non ciliated our sperms have cilia so they swim where they need to go fallopian tubes we saw are going to have ciliated because the egg doesn't have a cilia and a ciliated type is going to help move that egg forward so sperm carrying ducks and the ducts of large glands non ciliated types the ciliated pseudostratified columnar epithelium is going to be found lining the trachea found lining the trachea and most of the upper respiratory tract and most of the upper respiratory tract next to let's jump to stratified epithelium stratified epithelium now we talk stratified epithelium let's talk for a stratified squamous epithelium when we talk stratified squamous epithelium stratified men layers so too thick membrane composed of several cell layers now the basal cells the cells closer to the bottom closer to the basal surface those basal cells they are going to be cuboidal or columnar in shape they are cuboidal to columnar in shape and they are metabolically active cells now these cells are going to be cuboidal shaped so you're not going to use those to identify this tissue because then you're gonna call it cuboidal epithelium when it's not here you can see the surface cells these surface cells you see up here these cells you can see now they are flat they're flat they're squished and they're squamous shaped these are the cells you're gonna look at to determine this is being stratified squamous epithelium then we talk stratified squamous epithelium we have keratinized and non-keratinized in the keratinized type the surface cells are going to be full of keratin all of these cells they're going to be full of keratin and they're dead but here as we can see this is more of the non-keratinized type and so we don't see those dead cells and those basal cells are active in mitosis as we've described and they're going to be producing these cells that move up to the superficial layers so what's the function of having all of these cells the function is that these cells are all going to protect they're going to protect the underlying tissues in areas that are subject to abrasion right so we don't need those ourselves this type of tissue inside of the lungs now the non-keratinized type is going to form the moist lining of the esophagus the Mount and the vagina the keratinized type the keratinized type forms the epidermis of the skin which is a dry membrane it should make sense next in stratified cuboidal epithelium so some more images of stratified squamous here you have keratinized and non-keratinized here's all the dead cells that are packed with keratin you see right outside of here we don't have that here these cells are all living they have the nuclei inside of these cells don't have any nuclei so we talked stratified cuboidal epithelium and stratified columnar epithelium they're both quite rare in the body stratified cuboidal epithelium is found in some sweat glands and mammary glands and a stratified columnar limited distribution throughout the body next let's talk transitional epithelium when we talk transitional epithelium here we can appreciate transition epithelium transitional epithelium is going to be described as epithelium that resembles both stratified squamous and stratified cuboidal stratified squamous because it looks like many cells and up here you can see one row of flat squished cells stratified cuboidal because these look like a whole bunch of cubed shaped cells on top of each other the basal cells are cuboidal or columnar and the surface cells you see up here the surface cells are domed shaped or squamous like cells and that's all going to be depending on the degree of organ stress because if this organ is being stretched that those dome-shaped cells are going to be pushed down then because of everything being stretched versus them being here and being on the top so if we're to stretch it those cells are gonna start moving down it the function of this tissue that is that it stretches it stretches readily and permits distension of urinary organs by contained urine so the location where you find a step atheneum lining your you readers the tubes that take urine from the kidneys to the bladder the urinary bladder also has transitional epithelium and then part of the urethra also you're gonna find lining in here transitional epithelium or it's a lining type of tissue epithelial ms so let's talk then more image of transitional same thing here so here we can just see a nice epithelial cells right up inside of here so here the let's talk glands let's talk glandular epithelium now we talk glandular epithelium glands I want you to know consists of one or more cells that make and secrete a secretion which is a water-based fluid that usually contains proteins lipids or steroids now generally classifying our glands glands are classified according to two sets of traits the location of the secretion number one where they secrete their products and then number two we'll see the number of cells so when we talk first location of secretion when we talk occasion of secretion we classify our glands into two categories our glands are going to be classified as being either endocrine glands or exocrine glands when we talk about our endocrine glands endocrine glands are internally secreting glands they're gonna secrete into the interstitial fluid or into the blood second our exocrine glands exocrine glands as we see here they are externally secreting glands they secrete their secretions onto a surface or into a cavity onto a surface or into a cavity now we can also classify our glands according to the number of cells my classifier glands according to the number of cells we can see we can classify our glands as being either unicellular glands which is what we're seeing here one celled glands or they can be multi cellular glands where they're made up of many cells so let's talk specific classification we talk specific classification we have first exocrine glands exocrine glands they secrete their products onto a body surface the skin for example or into body cavities examples of exocrine glands will include mucous glands sweat glands oil glands salivary glands the liver and the pancreas now when we talked exocrine glands we said exocrine glands we have unicellular and we can have multicellular now when we talk unicellular exocrine glands an example our mucous cells or goblet cells these glands are sprinkled in the epithelium lining of the intestinal and respiratory tracts as we've talked about between columnar cells so goblet cells one example of unicellular exocrine glands and then the multicellular exocrine glands we can see here and we see here our glands that are composed of a duct not a quack-quack duck not d.u.c.k dct a duct and a secretory unit a secretory unit secreting component basically so let's talk about the different components first we have the duct so here you can see the surface epithelium and then here's the duct right the color is all color-coordinated for you so the duct the duct the duct the duct and the ducts we see here the ducts you see here and the ducts you see here so when we talk about the duct the duct you can have a couple of different types you can have either a simple duct or a compound duct the simple duct is a duct that has basically unbranched to it no branching to it so simple Ducks have unbranched ducks to them and when you talk about compound ducks compound ducks they're going to have a branched duct to them they will have a branched duct so here you can see simple ducks no branching simple ducks just here and here no branching here the duct the duct and then look at branches down to here the duct and the duct so these are compound ducks versus simple simple simple simple now the second part is the secretory unit we talked about the secretory unit the secretary unit can be either tubular where it looks or it forms you can see the secretory cells are gonna form tubes tubes tubular or they can be alveolar or they can be alveolar where the secretory cells form small flask like sacs small flask like sacs or you can have a mixture of the two you can have two below alveolar secretory units where you see both alveolar tubular alveolar alveolar tubular alveolar alveolar tubular alveolar so types of exocrine secretions cirrus glands they secrete thin watery fluid mucus glands secrete mucus that absorbs water to form mucus basically mixed glands secrete a mix of watery and mucus secretions and which oxide Aegina glands they release whole cells examples ovaries releasing the cells and we talk modes of secretion methods of exocrine secretions now how these glands secrete their products these glands can either be merocrine glands like our Akron glands where they secrete their products by exocytosis you learned in bio exocytosis is going to be vesicular transport out of the cell for example the pancreas most sweat glands and salivary glands we can also have holocrine glands which are glands that will accumulate their products within them until they rupture for example we have sebaceous or our oil glands and then third we have appelgren glands apocrine glands here we can see dont basically form droplets that bud from the surface and mammary an axillary glands will be examples of apocrine glands and here we can see american secretions apocrine secretions and here we have helican secretions now here we have tissue growth and development some terms I want you to be familiar with as well we talked about tissue growth or in relation to tissue growth we have first this term hyperplasia where we talk about cell multiplication hypertrophy where you talk about in an enlargement of the cells so here's cell multiplication versus enlargement of cells two different things and neoplasia tumor development and any changes you can have a couple different types of differentiation whereas we have a specialization of one form or function or you can have metaplasia then where you have a change from one tissue to another and then couple terms for repair regeneration and fibrosis regeneration is a replacement of dead cells fibrosis then is a scar tissue formation and then here's some terms in relation to that shrinkage and depth of cells atrophy or tissues reduction in the number of n size necrosis pathological death of the tissue and it could be due to infarction or gangrene where the blood supply is cut off an infarction or you have insufficient blood supply like with necrosis in gangrene or then the term apoptosis where you have programmed cell death and here you can see the gangrene and necrosis