so wrong button is it going to be one of those nights connective tissue and epithelial tissue there there are many sub-varieties of each one and this is an instance where um i have to praise your lab man you know in a lot of a lot of situations um with the lab manual i i remind you that it was uh it included things just to prompt you to go to better images in the book but there is a um there is a table on page 34 that quite nicely lays out not only the origin of connective tissue which mesenchyme which mostly comes from mesoderm but apart from ectoderm mesenchyme is not a germinal layer it is it is a type of cells that develop into connective tissue and stay with us our whole life the germ layers are just during the time that we're going through embryological development and then everything subdivides but mesenchyme is a type of tissue that's derived from the mesoderm and a little bit of ectoderm and presents all of your connective tissue so that's one of the things about connective tissue is it has a common origin and if you really just want to know a nice breakdown talks about what cells develop this particular type of connective tissue um and what the broad category versus the very specific name of each one and again that's on page 34. this slideshow is on blackboard by the way under your lab tab so um if you want to write while i'm talking because that helps you remember that's great but if if writing is distracting to you you've got it on blackboard so all righty there's four common types of connective tissue connective tissue proper which is subdivided into loose and dense and quick reference on 34 will show you the the names of those underneath it cartilage bone which henceforth you will not write bone you now know that bone is osseous tissue so you're going to write osseous tissue anywhere that the correct answer is bone you're going to write issues tissue because that's its proper name of this particular variety of connective tissue and then blood blood is a connective tissue and it is our only fluid tissue um so let's go through the characteristics of the general characteristics of connective tissue then we'll get a little bit deeper so we have living cells that are living within an extracellular matrix i.e these living cells create this stuff that surrounds the living cells that's what connective tissue is and this the stuff that the living cells either make or in are in blood's case are embedded within um is considered the extracellular matrix so connective tissue common origin mesenchyme it and consists of living cells within a non-living extracellular matrix because a protein is a protein but a protein in and of itself is not an entire cell is it it can't sustain all of the life functions that it that a living entity has so a protein fiber like collagen or elastic fibers or reticular fibers are non-living but in most of them are produced by the cells that are part of that connective tissue and so that's part of the extracellular matrix does that make sense okay i'm sorry the connective tissue well the extracellular matrix is actually considered part of the tissue itself so but that's why i slowed down to say the living cells and the non uh not only for example is it up here no it isn't um but on um on page 34 it talks about the different cells like um fibroblasts producing collagen um osteoblasts producing bone if it if they're listed and so yeah so those are the living cells creating their unique matrix which creates this subdivision of one connective tissue in comparison with another connective tissue they all have these generalized characteristics but these different cells thank you that prompted me to elaborate these different cells make a unique extracellular matrix specific to their purpose whether it be to make the fibers that turn into fibrin during coagulation in blood or to make the collagen lie down in such a way that it is very resistant to elongation in a tendon or collagen that's laid down in a very random way in several layers so that it resists movement in multiple directions like you find in a connective tissue i mean in a joint capsule and so those are actually a couple of different types of dense connective tissue i've discovered discussed dense irregular is the joint capsule dense regular is the tendon so in blood's blood fibrin is the fibers in blood okay um functions we've already started just talking about that to protect so in a lot of a lot of instances uh connective tissue will encapsulate like cartilage and bone rib cage protect the bones of your skull around your brain to protect to support connective tissue attached to the mesenteries in your gut to help suspend your organs where they're supposed to be to bind tissues together mesentery is another good example of that the capsule that encapsulates your kidney or the capsule that encapsulates your urinary bladder binds the other tissues within it because those are organs not just tissues so it helps to bind those other tissues together to help perform a specific function and repair scar tissue is collagen that's what scar tissue is um and in in in instances where you're dealing with tissues that don't does not readily regenerate you're going to have more collagen present and less of the original cells in that area which is why if you've ever seen somebody who's had um severe trauma to skeletal muscles in their arms or legs a lot of times you'll see where the trauma was it just looks like there's a scoop out of that muscle the skin looks pretty normal lying over the top of it and there might be a scar there but there's this big divot because skeletal muscle doesn't regenerate there's undifferentiated stem cells lying in weight but the uh the muscles the skeletal muscle cells that we have when we're born are pretty much what we've got so um so repair scar tissue different types of fibers collagen elastic in reticular we'll talk about that a little bit more the ground substance and we mentioned that the the um the indiv the individual cells of particular types of connective tissue produce this extracellular matrix that's unique to them so one characteristic of that of that extracellular matrix is the fiber the other is this ground substance and ground substance is glue and liquid and it can vary depending on the amount of ground substance in fiber proportion it can vary from almost like a gel like a rail or tissue that's right underneath your skin all the way up to very rigid and uh takes a lot of weight like osseous tissue so both have fiber both have ground substance but calcium phosphorus salts and hypoxia appetite minerals crammed together in spiral collagen osseous tissue is much more rigid and less forgiving than the irregular tissue underneath your skin that's almost goo so you see a vast variation in the even in different types of connective tissue questions about that okay let's look at some of these things we just mentioned derailer tissue so mast cells mast cells come from mesenchyme they are a cousin of basophils they're they do similar functions they release heparin they release histamine and are involved in inflammation reactions in the immune response but they come from two different parent lines so these mast cells are actually not part of the connective tissue they just they're just migrating through which gives you an appreciation of just how liquid this ground substance is and it's so it's so loose that cells can travel through it it's so loose that if you lose blood supply angiogenesis can occur and you can grow a new blood vessel right through that and in this in in the location that i just mentioned that it's right underneath your skin well you there's lots of blood vessels underneath your skin because that not only serves uh the tissues the epi the epithelial tissues of your skin but it also is very important in thermal regulation getting a lot of blood to the surface to get too much heat out so a rare tissue is very loose has a lot of elastic fibers that's those really thin long black ones that you see and collagen is stained with right stain it's it's the more violet you you don't see as many of these in this sample but there's a few in the background that are out of focus so and uh so it gives lots of capacity for things to pass through but it still gives a binding site for uh for your skin and for i'm um a blank but let's just leave it at that we'll go over some more examples as they come up so that's a regular tissue reticular tissue this is a wonderful wonderful slide that was created by a skilled person who made that particular slide by the way i should mention that this slideshow i've been given given permission by the person who made this slideshow to use it i did not create this powerpoint it was created by a master teacher that teaches at north georgia tech named kelly rhodes she's amazing she took the time to do all this and then turned around and said yeah you can use it what yeah i will because it's very helpful so um but she didn't do the slide it just prompted me to remind you because give credit where credit's due so reticular tissue so these little these little magenta globs that look like fruit on a dense tree or a bush those are the living cells those are the fibroblasts of this uh of reticular tissue reticular refers to a net if you look at the root of the word and you can see how this thin but long and interconnected collagen creates sort of like a net and all of the little magenta uh cells i say magenta because somebody told me that that's what it was i don't know colors of me that's purple but um but those are the cells that create that network so okay where would this be helpful in situations where you need a net or a some kind of uh jungle gym for cells to attach to so you find reticular tissue in sparse um you can find particular tissue in in many tissues throughout your body but there's a few places where you find it more voluminous more concentrated your spleen because your spleen filters tired in aging red blood cells and it just so happens that this the space in between those fibers are a little bit smaller than a red blood cell diameter and when blood and when red blood cells start to get old they can't bend and fold like they used to so they get caught in the net the other place that you find reticular fibers and and higher density is in your lymph nodes so your lymph nodes are there and it it's sort of a net but in your lymph nodes it's called stroma and that's that's the jungle gym reference i was referring to your immune cells will uh hang on to the stroma and just watch the cars go by so to speak and and when a bacteria or a virus or cancer cell comes by they'll jump on it and attack it so that's that's reticular connective tissue and it's most it's a net of thin collagen there's some elastic but it's mostly uh collagenous and you see the the reticular reticulocytes which are a type of fibroblast fibroblast is a very generic cell category of any cell that creates a fiber and then they get renamed specifically to their individual tissues so that was a loose type of connective tissue now we're going into dense regular versus cartilage and the reason why these two slides are are together is to show you the difference in the way the fibers are laid out and just to give you an appreciation of how things can look similar in some respects and very vastly different in others so um dense regular this is tendon and so these these are the nuclei of the fibroblasts within that tendon so not near as liquid ground substance as a [ __ ] does not have space for blood vessels to go through this so it's it's pretty much a vascular it's dependent on blood supply adjacent to it and there's so many collagen fibers packed in so closely that the nuclei of the cells that are producing that collagen get squished and flattened so they have that that very thin elongated appearance to it so that is dense regular it's it's more collagen than anything else then we get to fibrocartilage fibrocartilage is we're starting to get more and more solid with our ground substance i need to remember to point out one word back there behind me before we get too far away from talking about connective tissues but so now we're seeing a progressive rigidity and um the ground substance which brings up a new term that you're going to need to know called this isn't the word i was talking about but um lacuna it ends with a singular in lacun a ae plural so what is a what is a lacuna or what are lacunae well when your extracellular matrix gets so rigid that it it's more solid than it is gel-like it's more solid than in and less flexible the cells now so we crossed over to cartilage fibrocartilage so the cells that generate this extracellular matrix are called chondrocytes and that's cells of cartilage chondro refers to cartilage and so you see these nuclei of the chondrocytes that stain very well the space in which they reside are the lacunae that's that's what the lacuna is is the space in which the cells creating that extracellular matrix reside so let's put it in perspective you have this very enthusiastic cell that's been told make extracellular matrix okay i'm going to make extracellular matrix and so it goes hog wild and one day it realizes wait a minute i've walled myself in i don't have much room here at all so they turn from a blast cell a chondroblast which are referred to as immature cells that are prolific in their production of extracellular matrix to a site the first word i gave you chondrocyte the mature cell inside its lacuna and it's like you know what i'm not ready to die i don't want to squish myself with my own extracellular matrix so i'm not going to make as much but but i am just going to help maintain this that's around me so thus the space is the lacunae is the space that this cell that created the extracellular matrix resides within does that make sense okay yes sir can you hit the hide button on the um oh or what if i do no bam chondrocytes in a lacuna okay fibrocartilage fibrocartilage is the disc of cartilage in between the two halves at the where the front of your pelvis meet together the symphysis pubis that that disc of cartilage is made out of fibrocartilage and the annular rings of all of your intervertebral discs so at this point just no intervertebral discs between the vertebrae the bones in your spine are constructed of fibrocartilage and then we come to hyaline cartilage on the left elastic cartilage on the right hyaline cartilage this is the type of cartilage that lines all of the articular surfaces our articulation means joint the surfaces of bone meeting bone at a joint are covered with hyaline cartilage in fact if you look at this the the violet that that oblique strip from corner to corner is the hyaline cartilage and here you see transition to bone marrow here and up at the top so that gives you an appreciation of the work hyaline cartilage it just lies on top of other osseous tissue or isis tissue not other because hyaline cartilage is cartilage not osteous tissue and so the ends of your long bones where bones come together and form a synovial joint the other place that you find hyaline cartilage is the models of bone during embryonic development because hyaline cartilage can elongate much more rapidly than ossified tissue can so the majority of your skeleton in fetal development so frank here frank the fetus it's not real it's it's a model so frank the fetus is all hyaline cartilage at this point and uh over time that which you'll learn about here in a couple weeks it it goes to the process to turn over to osseous bone that's just compact so anyway so that's hyaline cartilage it's very rigid but it's not as hard as bone so it's like it's like this porcelain cup it's very hard but it can shatter with a lot of impact so we see the at this point the collagen fibers are so dense that it just looks solid you can't see anything in between the collagen fibers and there are numerous lacuna or cunei i should say properly instead of letting my dialect come out um and notice how there can be more than one cell in a lacunae in a lacuna or two lacunae just resting side by side you can argue either way so and this is mature hyaline cartilage so they're chondrocytes instead of chondroblasts because they are completely encapsulated in that space hi garlic yes sir um so it looks like there is actually or is it just we can't see the chondrocytes that are interesting you know sometimes they die and and yeah and uh the cell starts to break up the plasma membrane starts to break up and then it gets swept up in tissue fluid and then into the bloodstream so in in this tissue because this is so dense and it's a vascular so this would be adjacent to synovial fluid or and so it would be it would be taken up by the synovial fluid and then uh exported to blood good question elastic cartilage elastic cartilage is found in two places in your body mine is insufficient or just has more elastic fibers than collagen fibers which is why i have this holder for my masks because my elastic cartilage is so flexible that it will not retain a mask on my face so um so you find elastic cartilage in the oracles of your ear those funnels that funnel sound into your external acoustic meatus and the epiglottis the flap in your larynx that when you swallow it has to be flexible enough has to be rigid enough to uh deflect things that may be trying to go by it but soft enough to bend so that when you engage your laryngeal muscles to swallow and elevate your larynx the epiglottis can fold and seal so you don't asphyxiate when you're swallowing whether you're eating or or or drinking or constipated and doing a valsalva maneuver which i hope nobody's doing very frequently so elastic cartilage in the articles of your ear and the epiglottis in your larynx and very distinctive that you can see a lot of those darker staining elastic fibers there's collagen there too but there's a lot of elastic fibers in there and the lacunae are large and the nuclei of the uh chondrocytes in the lacunae are referred to as a fisheye lacuna so that's the giveaway for elastic cartilage um the borders of the lacunae tend to be darker i guess you consider that eyeliner if fish were island and and you get those big pupil nuclei that makes it look like fish eyes so that's elastic cartilage and so here we get to the hardest type of uh ground substance and that is calcium and phosphorus salts and hydroxyapatite which you don't have to know yet but um this is ostrich tissue and this is compact compact bone us compact osseous tissue and we know that because it looks like a a tree that the center rings have kind of rotted out and that's where blood vessels and nerve flow through solid bone and these this particular slide is referred to as ground bone um and they stain it differently and so these all of these dark dots that you see you you don't actually see the well we switched over from cartilage chondrocyte to osseous tissue osteocytes so you don't actually see the osteocytes because of the way this is stained so but the black dots are the lacunae that are present and they form themselves in what's referred to as lamela rings of of hardened extracellular matrix the calcium and phosphorus salts and collagen and they wrap in opposite directions for one from one another and so you get these these rings and depending on where it's located in that particular bone you'll see fully developed osteons or perversion systems that's what that's what the tree trunk looks like yeah is or you might see just some partial osteons filling in the gaps between two fully developed ones so that is osseous tissue and one of the easiest to recognize on plates and slides so and then we go back to another loose type of connective tissue um i should say loose versus dense if you haven't seen the if you haven't seen the pattern the looser it is the more the less solid the matrix the ground substance is and the less fibers that are present so that makes it looser not as compact does anybody know what adipose tissue was the giveaway right there fat cells adipose tissue my buddha belly is adipose tissue which is a form of connective tissue and um there are lots you can't really see them there's there's little collagen there's enough collagen to give some structure and support but it's mostly elastic fibers that weave in between the plasma membranes of the individual adipose cells why is it so elastic because most people most people in most lay people i should say who who haven't studied science think that as you let allow calorie consumption to get out of control and you start gaining weight that you make more adipose cells that's not true you your the number of adipose cells that you have is genetically determined through your family inheritance and that's pretty much what you've got like other connective tissues and other epithelials you can have some undifferentiated stem cells that can fill in the gaps if if a large portion of these die but um you've got a fixed number of sales so when you over consume and you start to gain weight these cells get bigger they stretch they just the the vacuole that contains the lipid just just get larger and when that stored energy is expended it will shrink back down but tissue lying over it like skin doesn't shrink back down quite as fast so um that actually makes liposuction not as safe as people like to think it is because your adipose tissue those fat cells actually produce hormones that have an impact on your metabolism has bearing on whether or not females begin to menstruate or whether or not they can even get pregnant because those hormones are there to let the body know yes there's enough energy storage here to support two people as long as we keep eating normally so if you go cutting out a lot of adipose tissue before you've finished or haven't quite made up your mind if you want to have a family or or maybe maybe one more then you could impact your capacity to get pregnant so um and the metabolism issue it can it can really set off your metabolism to cut out a lot of those anyway so that's fat cells um that's an interesting slide it's very clear and it's nice and rounded most slides of human adipose looks like cracked glass you know is this slide cracked because it looks like cracked glass instead of being really rounded like that and it also tends to be pretty easy to discern from others okay so that's the connective tissue now i just got excited didn't i just going all the way back so ground substance is made of fluid and i mentioned the word glue and that glue is proteoglycans which are uh a protein backbone or protein base that have gags the acronym gags is listed in your lab manual and this is why who wants to write out glycose aminoglycans so here let me maybe y'all see it now okay so glycosaminoglycans are attached to protein which forms like the the glue of connective tissue as part of the ground substance so location connective tissues now we got specific and in some of the subtypes in discussing where they were you did not see there is a picture in the text but there wasn't up here of joint capsule dense irregular connective tissue you did not see an image of that here but there is one in your book and it just looks like some person who is really into abstract art just through paint on the canvas so it's it's pretty distinctive um so it's found pretty much everywhere in your body because binding and in fact you will very soon learn as we start to talk about epithelial tissue that anywhere there is an epithelial tissue in your body there is connective tissue in your body because the basal portion of that epithelial tissue is always always always chisel it in stone connected to a connective tissue so um what is the um on the cartilage it said a vascular and lacks nerve fibers except outer ibd what's up oh oh wow we just did 37 we did all 37. cool okay 39 avascular and election except for outer um i don't know what that acronym is for gags every once in a while there'll be an acronym that's not a common acronym that i'm not avascular and likes nerve fibers except that is accurate because the outer one-third of intra-vertebral discs depending on who you read some people say third some people say uh 25 percent a quarter of intervertebral discs are innervated not vascularized but innervated that that would be accurate thank you thank you so that would be specific to fibrocartilage in because it's not true of hyaline cartilage okay elastic fibers blast sights okay mast cells got it got it got it good deal okay talked about that all right anybody else have a question find a hole that i didn't talk about i'm sorry blood okay so blood the living cells in blood are called formed elements red blood cells white blood cells and platelets which some people argue platelets are are not alive but it's got living cells creating you know part of the plasma membrane it does live for about 10 days so but anyway so those are the living cells the non-living extracellular matrix is plasma which is mostly water and solutes dissolved into it and um also the uh clotting factors and people say people want to argue that blood's not a connective tissue because it doesn't have fibers in it well actually it does but it it floats through plasma in a dissolved form called fibrinogen and when you have an injury to a vessel or tissue and you start the coagulation process chemicals in the platelets and then just from the tissue damage itself will create this enzymatic cascade to transform fibrinogen into fibrin and when when that enzymatic transition occurs the fiber comes out of being dissolved in solution and forms physical strands to help catch platelets and red blood cells and create a plug and make bleeding stop so that's that's how blood is defined as a connective tissue does that answer your question okay cool all right that was good anybody else before we move on okay adipose reticular epithelium all right oh i always forget to think i think about this in part two when talking about pregnancy i always forget it about forget about talking here embryonic connective tissue wharton's jelly um which i should remember because i lived through the uh i was no i was just out of grad school but anyway back in the george bush junior administration and i'm not going to get into the political arguments but um there was a big brouhaha about utilization of stem cells and stem cells research and you started getting all these stories about babies being aborted and grinding up the babies and using them for stem cells but that's actually not the source of the stem cells the source of the stem cells was the embryonic connective tissue in the umbilical cords that surrounded the umbilical arteries and veins known as wharton's jelly and the reason why those stem cells are so advantageous to researchers is if you get them in the right environment you can perpetuate them to divide and divide and divide and divide and divide so that you have multiple generations of the same cells so that you can take part of those cells and put them under a control situation and other cells and put them under an experimental condition and they're genetically the same so it's a nice way to be able to wade through any factors that might throw a wrench into your conclusions like you know we're two different people so that really dramatically diminishes how much we can say is true or generalized about research that's done on the two of us because we're both humans but there's a lot different about it he's got hair i don't among other things so um so that's one of the reasons why wharton's jelly was uh is is so uh coveted but also is a dangerous political topic because of from whence it comes all right so epithelial tissue so epithelial tissue is some of the most rapidly dividing cells that we have and because it has a lot to do with protection and absorption and secretion and you find them in rough environments like on the outside of our bodies rough environment our mucosa the uh linings of your nose the linings of our mouth the lining of our entire gut from just inside our lips all the way to the anus is covered with some form of epithelial tissue so protection absorption okay that makes sense in the gut doesn't it secretion well you have to secrete things in your gut too endocrine glands hormone-producing glands are epithelial if it if it's a structure and it has the word gland in its name it's mostly epithelial tissue because its job is to secrete filtration in your kidneys mostly the the tubules the tubule systems and the capillary balls and everything that's associated with filtering blood and reabsorbing stuff that we want to keep and secreting things that we want to get rid of epithelial tissue secretion sweat glands and other glands sensory reception um there are some epithelial cells that will uh that are modified and will encapsulate a nerve ending to help with certain modalities of sensation like deep pressure versus light touch and the it already gives it away taste buds uh our nerve endings go up in uh to a grouping and it looks it looks almost like an onion by the way they're oriented in this taste pour and it's because uh you think about your mouth we're putting hot liquids cold liquids sharp things and it's a rough environment so if we expose those nerve endings directly to all those things as you've already learned neurons are the easiest to injure and slowest to heal because they're so specialized so if we wrap those things in modified epithelial tissue well those are easy to replace a whole lot easier to replace than the nerves are so um but that's rare lots of stuff to talk about with um with epithelial tissue before we get into these i'm gonna switch slideshows on you and let's talk about nomenclature with epithelial tissue so epithelial tissue is polar it has polarity no it's not positive and negative polarity in in the instance of uh epithelial tissue means that one side is attached to something connective tissue and the other side is free to another environment like the outside of your skin is open and not anchored the inside of a blood vessel the lumen of a blood vessel is an open space compared to the basement membrane the that which i'll define in a second the inside of your gut the inside of your gut is technically on the outside of your body because this tube that starts up here and goes all the way the other end is continuous it doesn't stop and it's lined and that lining separates the rest of your body from inside that tube so epithelium so it's polar in that it has a basal surface basal base and an apical surface apical meaning an apex or a point and that so it's exposed to the outside environment that way okay um specialized contacts like the taste uh like the connection to connective tissue is supported by connective tissues everywhere every epithelial cell in the basement layer of stratified in every epithelial cell and simple epithelium is connected to connective tissue avascular but innervated so epithelial tissue does not have a blood supply it's a vascular doesn't have a doesn't have a blood capillary coming to it but it does have nerves supporting it that's what innervated me so it's a vascular doesn't have its own blood supply it's close to it which doesn't that make sense that a irregular connective tissue which is very loose and has lots of vessels going through it is really close to the basal layer of this epithelium because it's got to have blood it's got to have oxygen it's got to have glucose and metabolic waste exchange so it's a vascular but innervated it does have a nerve supply regeneration epithelial tissue as i said is incredibly mitotic it divides very rapidly so this is a tissue that can regenerate itself very well raise this back up so i don't have to bend over so far okay polarity we talked about that um polarity apical surface basal surface we talked about we you know so um and this is from chapter four you can get so you might have to go to the lecture side but you can get those the pearson slides from chapter from chapter four so so this is most like this is either in your gut or in your stomach it's um wait a minute yeah that's not pseudostratified so this is your gut or your stomach this is what's called simple columnar it's simple because it's only one layer thick it's columnar because the cells themselves are long and elongated like a column so this is simple alumni and down here is the connective tissue that it is attached to so this is the basal surface or the surface that's anchored and this is the apical surface the surface that's open to space around it so what connects the basal surface of an epithelial tissue to the connective tissue they're two different tissues ground substance is not alive how does the basal surface of this living cell get anchored to the connective tissue well the connective tissue produces some proteins and the basal cell of the epithelium produces some proteins like gags that it's like epoxy when they mix they harden and create glue and that's referred to as depending on where you're at and there's a little bit of difference but we won't get that nitpicky right now basement membrane or lamina propria so polarity always stuck to connective tissue at the basal surface via a basement membrane okay oh specialized contacts we talked about cell to cell junctions you you find them a lot and um in epithelial tissue particularly tight junctions the the protein that's like sewing thread that that attach adjacent cell walls and desmosomes not as gap junctions not as much okay talked about that in a minute okay where's okay here we go this is what i was initially thinking of but got sidetracked nomenclature for epithelial you've already been exposed to it and you already know it you just don't know it yet it's based off of nomenclature for epithelial tissue is based off of whether it's one layer or more than one layer if it's one layer it's referred to as simple if it's multiple layers it is stratified to be stratified or reinforced so if it's many cell layers thick two or more it's stratified if it's one it's simple and based on shape if it looks like somebody stepped on a boiled egg it's squamous if it looks squished it's a little thicker where the nucleus is but it looks squished and it doesn't have to be this regular either it could be a little more rounded um the the nucleus may be pushed a little to one side instead of being right to center but if if it doesn't look like a cube or a column it's squamous so these are the three shapes that you choose from so simple squamous or stratified squamous simple cuboidal or it's very rare but you can have stratified cuboidal simple columnar and even more rare is stratified columnar and so rare we really don't even talk about it but there's there are places in your pharynx where you have you can have some stratified uh columnar which gets confusing because of another specialized epithelium we're going to talk about which has a name that long pseudo-stratified ciliated columnar epithelium to be continued in a moment so simple or stratified squamous cuboidal or columnar let's go back to the other slide show real fast and then we can come back and look at these um you definitely need to look at multiple examples of this stuff so simple one layer thick the classic example of simple squamous is this so if you look closely you can see nuclei and epithelial tissue are uninucleate they only have one nucleus so every time you see one of those dots is another simple squamous cell adjacent to the other and in this example you have a very scant meaning of very little presence just enough to keep the cells together basal connective tissue why this is alveoli in your lungs so you're trying to get oxygen from the air inside your lungs into a capillary that's flowing close to that and you're trying to get co2 out of your blood back into so the thinner the interface the thinner the in the resistance from oxygen to going in to blood co2 coming out of blood the less labor cost it is to exchange respiratory gases so doesn't it make sense that this isn't really thick so simple squamous simple cuboidal in this case you have these q black shaped cells that form a tube so there's one tube created by simple cuboidal cells jammed in close together here's another one all of those are nuclei of simple cuboidal cells and let's see absorption and secretion that's kidney tubules so simple cuboidal kidney tubules simple squamous alveoli in the lungs we're back to the intestine or the stomach probably it could be either i can't really tell could be large intestine anyway the first part so here are three in this box and the apical edge depending on what the purpose of that cell is can be different see how this looks fuzzy that's because it has these long projections of long thin projections of plasma membrane that look like cilia but they're not cilia they are just projections of plasma membrane and what that does is dramatically increase the surface area of that cell which is advantageous when when you're trying to soak as much stuff up as it's flowing by as you can so um so this is most likely small intestine or large intestine so that's simple columnar and here is the connective tissue that it's anchored to here's the weirdo this is what it looks like spelled out pseudostratified columnar epithelium pseudo means false stratified you find this in the trachea and in this case these aren't microvilli they are cilia they are under power and they beat with a power stroke in one direction so why are they called pseudostratified because as they get crammed in tightly close to one another the nuclei get displaced some of them get pushed down closer to the basal surface some of them get pushed up closer to the middle and so it appears as if it's stratified based on the appearance of the nuclei but look at this one level that's covered in cilia so that one that one trips people up if you smoke stop because nicotine at first paralyzes these guys but eventually will kill them and that's what smoker's cough is and that's why so many people who smoke for decades have to manually clear their lungs out in the morning because they've killed those cilia now you know what the cilia do they beat up and they push the mucus that's produced in your trachea that has caught dust and bacteria up until you clear your throat and swallow yes it's gross but it what happens and so you you use you use nicotine and and the nicotine that you inhale and the carbon monoxide that you inhale paralyze at first and if you continue kill those cilia so now you're having to manually clear your lungs out not to mention emphysema but we'll talk about that in respiratory okay so you get that in part two so those are simple that's simple one layer thick and pseudo stratified which is still simple but we don't call it simple we call it pseudostratified columnar epithelium because it's so weird now we get into stratified squamous these slides are side by side because they are not the same this is stratified squamous so and this is the basement membrane of the basal layer of that stratified epithelium it's stratified squamous because they're relative they're pretty squished and just by experience i know that that's the papillary layer of your dermis the deeper layer of your skin the outer layer is epithelial the deeper layer are two different types of connective tissue and so this is skin stratified squamous epithelium as opposed to a very rare bird known as transitional epithelium so we have our connective tissue and then we see looks pretty rounded um is it squamous or is it cuboidal and and then you come up a little bit and it looks really round in some places and kind of squished and as you go up it changes size and it changes shape and then it really flattens out at the top so it transitions the shape of those cells transition they are epithelial cells and they are stratified but it's not stratified squamous why does it transition so much because this lives in environments where a tissue lining epithelium has to be able to stretch a lot the lining of your urinary bladder and the ureters the tube that goes the tubes that go from your urinary bladder up to your kidneys so that's where you find transitional epithelium this is what allows you to wait eight to ten more minutes to the end of the movie before you get up and run the bathroom it allows for more distinction without trauma if you try to stretch this it would just tear and there would be tissue damage this has a lot of capacity to stretch and in this urinary bladder this one's pretty empty why because you've got a lot of big rounded cells the more distended it gets the more squamous they appear does that make sense okay all right okay so there's that let's look at a couple of more examples in the other slideshow of epithelium these are nice because not only do you just see the plate but you also get to see an example of where it's located in and the generalized drawing of what type it is so again simple squamous alveoli in the lungs simple cuboidal again kidney tubules looks different doesn't it it's it these cells didn't those cuboidal cells didn't draw up quite as much of the stain didn't absorb as much of the stain as the other did but the connective tissue around those cuboidal cells did simple columnar this is stomach this i mean this is good and this is this is a this is a fold in your gut whether it be a circular fold which you'll learn in part two and uh so that's a mucus plug that that is a goblet cell which is a specialized a goblet cell this is more like a goblet cell a a goblet a glass that that's uh cylindrical at the base and as it comes up it it gets bulbous or a goblet so if you look real close basement membrane nucleus relatively columnar and it both it bulges out and in comes bulbous that's that's where those cells get their name and goblet cells are columnar epithelial cells but they are specialized to produce a copious amount of mucus so they're not those aren't absorbing they're secreting the ones next to them that have this brush border the microvilli to increase the surface area they're the ones absorbing so secretion absorption so if you if you spend some time with it and start to learn the functions it'll it'll start to click where this stuff is located secretion goblet cell gut absorption gut protection stratified so that you have many layers that's more resistance to abuse or inside your bladder transitional more layers will allow to stretch but also because it divides so quickly some of the layers can get eroded by the acidity of your urine or the presence of urea or ammonia in there in there and it gets replenished quickly protection so there's there's so it starts to make sense at least to me pseudostratified so we get to see a nice goblet cell stuck in that stuck in that pseudostratified and so now that the top of this goblet cell is is obscured by another cell because the goblet cells are not ciliated they just come to a point and secrete mucus so those cilia are associated with another cell because remember these are packed in so tight it displaces the nuclei up or down giving it a stratified appearance when it's not again in your trachea skin again another view of transitional epithelium so ureters and urinary bladder glands okay that's going to go off into something else okay so all right clarity protection absorption if you're overwhelmed that's okay it's it's a lot and i have never met a student who has including myself back when i was one that was not a bit overwhelmed by all of this um and those of you who come to the asap before the semester and hurt us just rant and rave about well this is one of those perfect examples of you just have to spend the time there's no other way around it you just have to spend the time with it um okay i mentioned it but i'll i'll mention it again because you know rare things tend to wind up as test questions um so these are so rare i typically don't throw them out there because i want i want you to understand the concepts first i want you to know concepts i want you to know what normal is because then you can i know normal that looks different so what do i need to know because that doesn't look normal but that's not to say that questions about stratified cuboidal or stratified columnar won't come up on a midterm or a final lab exam because those are departmental and i'm not the only one who has input in it so you will hear me say that from time to time because i want to move things along i also want you to be prepared and we're all every one of us have our own little rabbit holes that like that we like to go down okay stratified cuboidal we mentioned like sweat glands and ducts from large glands like the duct that goes from the cells in your pancreas out to your gut um stratified columnar the pharynx the male urethra and only the male urethra not the female because those are ciliated to help in the reproduct not not with the urinary system not with excretion of urine but with the excretion of sperm the cilia during ejaculation will beat out toward the head of the penis to help propulsion of um of semen out and then let's see some glandular ducts yeah we talked about that transitional we talked about okay good deal okay endocrine gland versus exocrine gland since it's here they're both glands so and i mentioned if it has the word gland in it it's got epithelial tissue in it the difference between an endocrine gland and an exocrine gland is that get rid of this stuff now that you've got it down an endocrine gland makes its product and just releases it into the interstitial fluid right outside of itself and they almost always live next to a network of capillaries which will very quickly pick up that product and carry it through the blood because what what what do most endocrine glands make hormones so long-distance chemical messengers so endocrine glands endo create their products within the gland and just release it into the extracellular space or interstitial fluid interstitial space to you same environment if you remember from last lecture as opposed to an exocrine gland and to make it even more complicated there's weird things like your pancreas that do both exocrine glands also epithelial tissue produce their products within themselves but they dump or release or secrete their products into a tube a duct and that duct communicates with a nearby environment like sweat glands like again your pancreas the endocrine portion of your pancreas creates hormones that are associated with blood glucose regulation insulin and glucagon the exocrine products of your pancreas are digestive enzymes digestive enzymes for our macromolecules carbs lipids proteins and nucleic acids and they are dumped out through your pancreatic duct rare stratified cuboidal into your duodenum the first section of your small intestine so endocrine gland makes its product just dumps it in just dumps it outside itself into the extracellular space and it gets picked up by capillaries and dispensed that way exocrine makes its product and releases that product into a duct that is going to convey that product to another environment endocrine exocrine membranes we talked about dry membranes skin and wet membranes to serosa that's about all you need to know about that okay um tissue repair since we talked about connective tissue collagen being involved in tissue repair there's a process please refer to your text that are the page numbers in there and is it the right addition um it'll be at the end of chapter four and it'll be a discussion about this the processes that occur at the after you've had tissue damage you have tissue damage you have bleeding you have coagulation you have fibroblasts migrate to the area and start to lay down scar tissue and then the epithelial lining will will cover the top of it so that's a nutshell but do go back and read it because i just i just threw it out there um all right fiber scar tissue yeah that that's a rabbit hole in and of itself fiber scar tissue scar tissue is mostly collagen collagen is piezoelectric you're right collagen's a a a candle lighter or a cigarette lighter because those are piezoelectric well yes those are piezoelectric but what does piezoelectric mean piezoelectric refers to substances that when there is stress placed upon them generate an electrical current so your bones do too but we'll talk about that later so collagen is p piezo piezoelectric when there's stress put on it it will generate a very tiny electrical current that will run through it and affect the behavior of adjacent collagen fibers over time as collagen fibers mature and it's real loosely related to this they shorten and stiffen and shorten and stiffen and shorten and stiffen which is why people like me pts want to stretch stretch stretch stretch because if you don't manage the length of scar tissue over and and the hard thing to do is to get your clients to continue to maintain the length of that scar tissue after they've been gone from because they're like okay i'm done and then eight ten weeks later they come back what happened i was great and now i can't straighten my knee you quit stretching the scar shrank and you're stuck i.e the last part of that that i was going to tell you is collagen shortens and stiffens and shortens and stiffens and when it becomes fully mature loses its elasticity and the average timeline is around six months and if it's just in a tendon that isn't stuck to anything else it's not that big a deal because there's enough elasticity in the the uh contractile elements of the muscle cells that you can get away with it but if it's close to bone or if there is an adhesion meaning the scar t because scar tissue when you have uh tissue damage and you have coagulation to stop bleeding and then the formation of scar tissue it does not discriminate tissue types it doesn't care if it's epithelial or connective tissue or osseous or cartilage it's going to glue it all together and poor scar management and areas where there's lots of different structures that have been adhered together and an adhesion by clinical definition is where you have a layer of tissue that you want to move that is very restricted because of that scar tissue has set in and not allowed it to be able to uh to glide like it should in early early knee replacements and i've been around long enough to see still what's relatively early knee replacements the protocol was lock them in an immobilizer and let them start to heal because there's been so much trauma to that tissue well then you started having people who couldn't bend their knees or they start to climb the stairs and and they would have the severe pain because the skin on top of their kneecap was adhered to their kneecap and when their kneecap stopped moving and because of that loose [ __ ] tissue is no longer loose it's replaced by scar tissue that skin can't move and it stretches the dog mess out of the nerve endings in the skin and now they don't want to walk and they want to sell their house so that they can get on a one-level house because they're i ain't going up them stairs what's up there i don't care i'm not going up those stairs it hurts too much so that's what an adhesion is um when adjacent tissues that normally are not stuck together are stuck together keloid scarring um i like to tell this story i knew this for many years just because of my education but then i had an aunt that went and did like the 23 of me or one of those things to find out that there's most of my uh dna comes from scandinavia but at least three percent of it comes from east africa and i i grew up in a family that i'll just say thank god for my maternal grandmother um because there was a lot of hate on my father's side of the family and if he only realized that he married into a family that had three percent of african blood in it he would go berserk he's rolling in his grave right now i'm sure but so why why where did that come from keloid scarring or hypertrophic scarring where you would have an injury and instead of having a normal deposition of collagen enough just to fill in the space and restore that damage you have in some instances a just tremendous amount of collagen that's laid down and so you develop hypertrophic scars or in the more severe situation keloid scars where somebody pierces their daughter's ear and instead of just being a pierced earlobe because of the scarring process it looks like they've got part of a cauliflower now because they had so much um collagen that was produced me on my back when i was a teenager and had acne i have hypertrophic little spots that came up and so when i got into grad school learned i'm like okay and and i just had this little secret laugh at my dad anyway um so that's keloid scarring just massively over college overly um productive scar formation after an injury that results in mouth-shaped repair and then cancer if you start paying attention you will see that cancer almost always is associated with cells that divide quickly like epithelium leukemia blood cells and well leukemia is white blood cells and it's if they divide quickly especially um when you have an immune response come up so what happens is during during the dividing process normal dna replication goes awry and things don't get replicated accurately so what would so that cell cannot perform its normal function it's going to have abnormal function from then on so um okay and y'all can benign malignant metastasis that's easy enough to learn okay because it's getting late i'm starting to lose you i can tell people are fading okay questions concerns it's going to be it's going to be mostly like tonight yes so that you you'll have some questions that you answer about tissue types you'll visually identify i'm not it's if if nothing else it's a little cya not having uh you know if we set up microscopes and allow you you can choose to look at this or not that's one thing but if i set up a testing situation where 20 people have to look through the same microscope and somebody gets really sick because of it yeah so it's going to be like tonight the images yes ma'am so um any other questions you'll be like function location of your description right and uh so function location um and characteristics too don't forget so connective tissue protects supports binds uh epithelial tissues are lining secretes absorbs and protects so need to know those things too and for this one now midterm and final you'll have questions about all of the tissue types but we did nervous and muscle tonight and next week is going to be restricted to connective tissue and epithelium but and a lot of students feel like after they get through 2a and 2b they don't have to remember anything about tissues yes you do because as we discuss organ systems we're going to be talking about this is made out of that and remember blah blah blah and so midterms and finals it's very common to have an image of a connective tissue and ask you like um something like okay the inner tunic of your gut this is like a part two question um the inner tunic of your gut is lined by what and they'll be pictures of six different tissue samples there and you have to pick the one that's right simple columnar or in this case it might be um just anything related to tissue over something like skin integumentary system um same scenario pictures of tissues and it's and it won't it wouldn't it won't be as easy as answering what tissue type is the epidermis because you spend a couple hours talking about that and it's stratified squamous so that's not going to be the question but what's the deep layer of the dermis made from it's called reticular but it's not reticular connective tissue it's actually dense dense irregular so so and you'll know that by then but the point is after you get through this past week and after you get through the next week you you you can't open your head and pour all that knowledge out you've got to keep it in there so um does anybody want to look at real tissue slides okay so i'll pull out a couple if any of you who who is exhausted need to go may go those who want to stay and hang out i'll pull out some uh some slides of a few different types of epithelium and connective tissue and we'll put them up on microscopes so thank you let me capture this video