alright guys this is part 2 of the chapter for tissue packet alright so again we're gonna be talking about tissues which are groups of closely associated cells that work together to provide common function alright and there's four different types of tissues you have epithelial tissue you have connective tissue you have nervous tissue and you have muscle tissue and chapter four really highlights the first two epithelial connective and that's Brett that's how we're gonna approach tissues in this first I had exposure to tissues we'll talk later about nervous and muscle later on when they have their own packet all right so connective tissue is still very similar to epithelia and the fact that there are groups of cells that work together to provide a function okay and the difference is that it's totally different though alright so this is the same analogy I gave when we're talking about epithet connective in lab okay I'm gonna give it here also in lecture okay so you can think of these two as two different sports right so what's the what's the what's the commonality I say between baseball and basketball well they're both sports all right same thing if I say what's the commonality between epithelial tissue and connective tissue well you can say that they're both tissues all right the difference is well baseball and basketball are totally different sports same thing with epithelial tissue connective tissue totally different tissues so when I think about an epithet tissue I'm thinking about a sheet of cells right and these cells are pretty much all identical to one another but when I think about a connective tissue well I'm still thinking about a group of cells but it's not a sheet of cells anymore okay it's very possible that you know there's many different kinds of cells that make up a connective tissue okay if I think about baseball you're talking about things like right home runs and hits and and walks and RBIs and ER a all right you're talking about basketball you talking about dribbling and passing and shooting right and free throws and three-pointers okay lateral movement and defensive stands and all that stuff right so when you think about epithelial connective tissue they're both tissues but they're way different from one another all right so if you guys recall and when I ever talked about an epithelial tissue okay it was supported on the basal side by what well it was supported on the basis I'd by the connective tissue alright so connective tissues their overall function is binding and supporting so in that idea of a connective tissue okay supporting an epithelial tissue on the basal side of an Epiphone alright so besides supporting episode what else does it support well it supports okay other tissues of the body binds together things like tendons and ligaments are considered connective tissues okay and when you think about okay blood okay that helps you transport gases helps you transport nutrients helps protect you against infectious microorganisms because blood has white blood cells when you talk about support when you think about cartilage and bone okay cartilage of bones are considered okay connective tissues so of the different tissues that are out there epithelial connective okay nervous right and muscle connective tissue probably is the most diverse right some from something as solid as bone osseous tissue to something as liquid as blood a matter poetic tissue okay all under the same rubella we call connective tissues right so when you think of connective tissues there are four different classes right and within each for the different classes you have then subclasses so the four main classes of connective tissue they are the four main types of connective tissue are connected tissue proper okay this one you think about like adipose tissue like fat reticular tissue okay areolar connective tissue dense regular dense irregular dense elastic okay those are all examples of connective tissue proper all right now the cells I think about when I think of connective tissue proper I think about fibroblasts and fibro sites all right the second class of connective tissue right its cartilage so when you think of cartilage right you think of something that has a watery matrix so something that can resist compressive forces okay at the same time it's very possible these have fibers so they also can resist tensile forces they can resist pulling forces right so these are cartilage when I think of cartilage that the type of cells I think about are chondroblasts and chondrocytes all right the third class or type of connective tissue is osseous tissue okay bone all right and there's different kinds of bone there's there's compact bone and there's spongy bone right here's a micrograph of compact bone right here all right I think of something that's solid in many cases something that's a very protective something that supports okay when I think of bone tissue I think of osteoblasts and I think of osteocytes in terms of cells all right and the last type is the most atypical okay of the four different classes of connective tissues right and that's blood I'm at a poetic tissue okay so this one here is not a solid it doesn't bind anything together it doesn't support anything right so what is it doing here okay these all bind the support what's blood doing well we're gonna figure out why we consider blood part of a connective tissue or a class of connective tissues now in terms of cells you think of red blood cells all these pink ones here you see without a nucleus you think about these larger ones with the purple nucleus okay these are the white blood cells you also think about these little tiny tiny specks right here okay well these ones represent a the platelets all right so what's gonna join these four classes of tissues together connective tissue proper cartilage bone and blood well one of the things okay that joins all four together under this umbrella of connective tissues is where they come from embryonic Lea okay they all have the same embryonic origin okay they come from an embryonic tissue known as mesenchyme alright from an embryonic tissue known as mesenchyme so if your mesenchyme you will be a connective tissue right so if I'm messing kine and I've become a fibroblast which then matures to form a fibro site or then you're gonna become connective tissue proper okay you're gonna become these ones down here areolar adipose regular irregular elastic however if I'm messing chyme okay and I now differentiate into a chondral blast which then matures into a chondrocyte well then you're gonna be cartilage okay you're gonna be the things that we saw in lab hyaline cartilage fibrocartilage or elastic cartilage well what if you're messing kind okay and you become an a steel blast instead which then matures to form an osteocyte well they're gonna become osseous tissue you're gonna become bone okay and there's compact bone okay the type of bone you think is solid like I'm the outer surface of a bone and then you have what's called spongy bone or Kant cancellous bone okay which is kind of a wafer branch-like bar like bone inside of your bones so those arrived for mesenchyme or if you're medicine come you can become a home at of poetic stem cell okay which then matures to form the blood cells becomes a red blood cells okay becomes the white blood cells it becomes the platelets you become blood so the reason why we consider connective tissue proper we consider cartilage we consider bone we consider blood all connective tissues is because one they have the same embryonic origin they they are derived from an embryonic tissue known as Mezen kind okay so is that it is that the only reason why we linked these four together as connective tissues well there's other things okay the second thing is that they're generally okay supplied by a lot of blood vessels okay they have a rich supply of blood vessels so whenever for example I drew an epithelial right we know that there's polarity to an epitome there's an apical side to an epithelium right and there's a basal side tune up with them so let's say here's that boundary between the two and we're gonna just gonna draw a simple squamous epithelium here where one side is exposed to a free space so this is the apical side okay one side is supported by a connective tissue so this is the basal side of RepA them okay we know that the epitome is a vascular mean that doesn't have blood vessels but connected tissues generally speaking okay they're very richly supplied with blood vessels okay so here's the lumen of our capillary right there's blood contained in this lumen over Kapler okay and then again lining our capillaries again would be a simple squamous epithelia here okay so we can filter things out of your capillary into the surrounding connective tissues right so if I have now let's say something here I can through the process of filtration push it out and now it's present within the fluid of my connective tissue okay so generally speaking we think of connective tissues okay there where it very well vascularized all right thirdly okay when you think of connective tissues and there's some exceptions I'm sorry guys to being okay very vascularized cartilage for example tendons ligaments k are not vascularized all right three connective tissues are composed of many different cell types alright so going back to that that picture that I just drew actually okay when I think about empathy lacell right pretty much this cell here is identical to that so there is identical to that so it's done okay these are all pretty much the same cell okay think of a tiled floor again okay if you look at a tiled floor they're pretty much all the same tiles making that one floor now you may have an accent tile in there somewhere okay for an epithelium you may find a goblet cell maybe scattered in here right but pretty much all the cells within that sheet of cells are pretty much the same okay when I think of now a connective tissue though okay you are now looking at okay many different kinds of cells so here's one cell type we'll call this cell a okay there's another cell a over here right and then you have a different cell type well make this may look a little bit more different okay here's Selby alright and then somewhere in here all right you have a cell see and so forth and so on so when you look at a connective tissue well number one the cells aren't joined together at their lateral boundaries there's no desmosomes for example holding these together okay there's no gap junctions allowing them to communicate right now these cells are kind of spaced far apart not far relatively speaking they're still close to one another about the relative to an epithet so they're farther apart alright and there's many different kinds of cells that come together to make a connective tissue all right now the fact that there's space that's outside in between them well their stuff outside in between them now all right so one thing that we can filter out of your blood is war right so let's say this is what these blue things here were water okay so now I have a watery environment that surrounds and bades myself all right and what's the name of that fluid that surrounds and bathes your cells well we can't again we call that inter Stickle fluid okay so there's there's a fluid that surrounds it okay on top of that okay we did kind of introduce this kind of stuff when we're doing cells there's there's there's fibers that run outside and in between yourselves all right we're gonna learn that some of these fibers are called collagen fibers some of these fibers here they are called elastic fibers some of these fibers out here are called reticular fibers so the fact that the cells now are spaced out suck okay away from one another okay we now have space for interstitial fluid we have space now for all these fibers that run outside and in between ourselves okay and that leads us to the fourth thing when you think about what joins connective tissue proper okay cartilage bone and blood together okay well one is messing kind a two they're typically very well vascularized there are some exceptions three right instead of just one kind of cell making of a connective tissue you have many different types of cells that make it up and four okay little Keanu Reaves action here the matrix okay so that thing that's outside in between cells we call that the extracellular matrix extracellular means outside so all that stuff the fluid the fibers right we call that the matrix of the extracellular matrix it's what distinguishes connective tissues from epithelial tissue for example from nervous tissue from muscle tissue so where is the matrix produce where is that fiber is produced okay where's the the thing that holds on to the interstitial fluid proves was produced by the cells of the connective tissue so the cells of the connected should make it okay and then it is extruded out of the cell so now that we're outside in the sauce so the matrix okay and not the cells okay accounts for the strength of the connective tissue alright so before I talk about the butt dot dot dot over here right when you think of connective tissue okay it has two things one it has cells because that's why it's a tissue right and it has a matrix so if it has cells any matrix well then you're dealing with a connective tissue okay it's the matrix part though that accounts for the strength of the connective tissue why because of the fibers right those fibers that are running outside in between cell that accounts for the strength of a particular connective tissue but what well they're not all the same so the reason why okay bone is different from cartilage is different from connective tissue proper is different from blood is because okay one the type of cells but also okay its matrix okay so it's the matrix and the fibers of that matrix that accounts for the strength that we connected tissue all right so here I see a figure of different cell types right running outside in between I see these these blue fibers alright and these kind of purplish fibers okay and also see this brown stuff that's out there all right so that's the matrix that's the extracellular matrix that's surrounding these okay five cells okay the first thing we talked about is this brown stuff back here okay not the fibers yet okay and the brown stuff is called ground substance okay ground substance is the part of the matrix that holds on to the interstitial fluid that holds on to that fluid that leaks out of your okay that is filtered out of your of your capillaries okay so it's because of the ground substance okay it okay it creates this watery environment it creates the medium by which things can diffuse so if I go back to this picture here alright and now I have a watery environment because the ground substance is holding onto stuff okay what if now okay this is glucose okay and I filter the glucose out well now this is not a dry environment this is a watery environment okay water and interstitial fluid held on by the ground substance now what can I do I can now diffuse okay and now reach my cells okay and now again we have a happy cell here again happy happy happy okay all right the second component of the matrix alright again are the fibers all right and there's different kinds of fibers you able to call collagen fibers you have okay elastic fibers you have reticular fibers and all three of these fibers are produced by a cell that's part of this tissue known as a fibroblast okay so there's a fibroblast now let's do a side-by-side comparison okay that's gonna relate to this particular side here okay so let's actually read this slide and then we'll go to the our pseudo whiteboard alright the types of fibers okay so again there's collagen fibers there's elastic this particular the density of those fibers so you have a lot of those fiber so you have less of those fibers okay and the distribution of those fibers okay where you find them okay are distinctive for each type of connective tissue alright so if I now okay go over here and let's say I'm doing a side by side comparison to two different connected teachers I'm not even I'm not even naming these connected teachers I'm just giving them okay connect the tissue number one okay versus okay connective tissue number two okay and what are the two things they better have if they're connected tissue well they better have cells okay so there's a book enough cells and they better have a matrix all right so let's say connect the tissue one okay has lots of cells okay and not so good of a matrix in terms of well-defined matrix as opposed to connected to two has you know not that very many kinds of cells okay but it has a well-defined matrix hey and the two were trying to compare right it's bone in blood which one of these describes bone which one of these describes blood all right so which one of these would be blood what blood I know has the red blood cells and it's white blood cells and has platelets and there's a lot of them Hey so it's looking like this right here right it's blood all right so for blood we're thinking about all right red blood cells white blood cells all right and platelets hey it's matrix well it's the fluid part of our of our blood it's called plasma so this first one here well this is blood so describe blood to me okay is it something that supports something that binds something that okay can how to hold things together no why why is it a really weak connective tissue okay it doesn't support anything it doesn't buy anything because look at its matrix okay its matrix has what okay no collagen fibers okay no elastic fibers no reticular fibers so that that's why blood is the most atypical connective tissue it's matrix doesn't have any fibers as opposed to connected to okay this is probably bone why is this bone well because it doesn't have that many different kinds of cells right yes it has osteocytes all right but not very much Brian not very many either but its matrix is what it has a calcified matrix okay it has a hard matrix it has collagen fibers for example in it all right so this one here is very right strong why because look at its matrix its matrix is very well defined here so depending on the types the density the distribution of these fibers okay it will dictate okay the strength of our connective tissue we connected tissue strong connective tissue all right so we already know there's four different classes connective tissue proper cartilage bone and blood all right and under each class there are sub classes for example connective tissue proper has areolar it has adipose it has reticular it has dense regular dense irregular density elastic so there's got to be something different so that now there are subclasses there's got to be something in terms of their cells and matrix that make something different from one another because if they were the same well then why do I need subclasses they'd all be the same all right so in terms of cells we know that there's a hundred trillion cells in our body as adults okay and there's two hundred and ten different kinds of cells so when I was doing chapter two with you guys and I started to talk about cells okay did I go over all 210 the answer is no right all I did with you was gave you a generalized style I gave you a pimped-out cell that had a plasma membrane that had the nine different types of organelles and that had a nucleus so now every time you come across the cell and I say you want guys this is just like that general I saw that we talked about what it doesn't have any of this or it has a lot of that okay it's the same thing here hey we are going to talk about all the different kinds of connective tissues we're not going to skip it like we did with the Scout cells but before I talk about all the different kinds of connective tissue we're gonna talk about the pimped-out connective tissue we're gonna talk about the connective tissue that has one that has different kinds of cells that has a really good defined matrix that has all the fibers that has a good ground substance okay in the name of that connective tissue that's what we call the proto typical connective tissue we call it areolar connective tissue okay it's the most abundant in the connective tissues right it underlines almost all epithelial of the body and surrounds almost all the small nerves and blood vessels so if I go back to a drawing okay that we did for the first part right of this packet okay something that looks like I like this right where I have an epithelium and supporting it I have a connective tissue alright so here's my epithelium on top right and on the basal side here I have a connective tissue so every time I drew an epithelium I showed you supporting on the basal side a connective tissue well we always work off very general in this class and get very specific well now you guys know on that basal side of an epithelium well this is a real large connective tissue now okay so supporting right not just epithelium but supporting other tissues body here's just a good example something you are familiar with okay is areolar connective tissue alright so if it's a connective tissue you better have cells I'm looking here has different kind fat cell plasma cell mass cell fibroblast Micro fate and I better have a matrix I see a ground substance I see collagen fibers I see reticular fibers yeah I see elastic fibers right here all right so it has cells and it has a matrix now because it has everything because it's what we call the prototypical connective tissue what do you think the function is do you think you could do a lot of things that a connective tissue to do or do you you can it only does a limited things that a connective tissue can possibly do well based upon the structure you pay it based upon the fact that it has different kinds of cells it has a well-defined matrix okay it does pretty much everything a connective tissue can do and those are four things number one right it supports and binds other tissues why do you think that's because of the matrix of areolar or do you think it's because of the cells are very large supports and binds do that's because of the cells or the matrix again if you're understanding this you're probably saying matrix it's the matrix that accounts for the strength of a connective tissue remember that slide hey why because of the fibers number two it holds body fluids is that because of the matrix of areolar or because is that because right of the cells of areolar well if you're understanding what I talked about well the second part of a matrix is ground substance right and it's the part is the job of the ground something it's a sponge that holds on to them that interstitial fluid that then bathes and surrounds yourselves so supporting and binding holding body fluids that's because of the matrix are very are three defends the body against infection from microorganisms hey do you think that's because of the matrix or the cells are very or well it's because of the cells it's because of cells like macrophages it's because of cells okay like mast cells it's because of cells like plasma cells that were able then to do number three defend the body against infection for microorganisms so if I'm doing checklist number one that's because of the matrix number two it's because of the matrix number three it's because of the cells and then number four areolar is good at storing nutrients in the form of fat is that because of the matrix of areolar or is that because of the cells of areolar what's because of the cells right cuz it's right here looking at you right in the face it's called the fat cell it's called an adipocyte something that you guys already saw right in lab so right here okay there's an inclusion called the lipid droplet and inside of there is fat so for okay it stores energy in the form of fat why because it has adipose cells it has fat cells okay so this is our prototypical connective tissue right so what type of fibers do I find well you find collagen fibers in areolar it's the strongest in the most abundant type this is these big thick blue ones right here okay and these collagen fibers you can actually see we actually separated them out okay are composed of okay okay little tiny collagen fibrils hey and these little collagen fibrils are crossing together to make this thicker collagen fiber so what is the job of a collagen fiber it helps with Stan tension and that's just a fancy name for pulling forces so if I take my tissue and I start to pull and tug on areolar well it's gonna help resist a little bit of that pulling and tugging why because the matrix of areolar has collagen fibers present in it okay and again who makes the collagen fibers you can actually see these big purple cells here these are called the fibroblasts these are the ones that produce the fibers all right the second type of tissue that's issue but fiber that you're gonna find in areolar you're gonna find reticular fibers okay and you see these blue ones these fine blue fibers right here okay they're actually made of collagen okay but the collagen is a lot thinner a special type of collagen okay and their job reticulate reticular you guys have heard of endoplasmic reticulum okay it means network so we have a network of these fine reticular fibers they cover and support all the structures that board the board of the connective tissue so it surrounds capillaries okay it borders the epithelium why because the function of reticular fibers is support all right so do you guys remember when we're talking about part one of this packet and we talked about the basal side of an Epiphone right so what's one thing that we find okay on the basal side well you find a basal lamina right it's a non cellular sheet let's draw a little thicker okay it's a non-cellular sheet produced by whom bruce by the epithelial tissue and then what well now you have also have reticular fibers that are produced by the connective tissue so what do I call the basal lamina and purple and the reticular fibers in red together or you call that the basement membrane right so here we see reticular fibers from this aerial or connective tissue supporting the overlying epithelium okay so the job of reticular fibers is support all right so they're not gonna suffocate okay for example the structure supporting they're not gonna choke them out for example we find reticular fibers that surround your capillaries okay but they gently support these structures right the third type of fiber is the one here kind of in a brownish orange right we call these elastic fibers and these are made up of a protein okay called elastin and they're kind of like rubber bands basically what happens if we lever bettan you can pull on it you let go what happens remember when it snaps back into shape it recoils back into shape okay so if I pull on Airy or what's gonna help resist the pulling force well that's the collagen fibers in blue okay but if I let go of areolar what happens well because I have elastic fibers well then I can snap and recoil back into shape without elastic fibers if you were to pull an area large can be like a piece of taffy you stretch it out and it's gonna stay stretched okay but we have elastic fibers we have the ability to recall or snap back into shape all right so besides having all three fiber types hey what else is aerial or having its matrix well it has a pretty good ground substance okay so the ground substance again is the stuff that's outside in between yourselves okay it's the part that holds on to the tissue fluid it's the part that holds on to that interstitial fluid that comes from the blood right so provides the medium they were getting which wastes and nutrients and other dissolves can diffuse between the blood and the cells all right so we can think of the ground substance as a sponge the sponge that holds on to that tissue fluid to that interstitial fluid okay and what makes up this ground substance are large sugar okay called glyco aminoglycosides likeit's right and these combination of these two allow the ground substance to soak up the interstitial fluid to hold on to that tissue fluid derived from the blood much like a sponge all right so that's function one right in terms of support and bind function two holds body fluid function three again was what fight's okay in defense your body against infection again that's not because of the matrix it's because of the cells so if I look at the different kinds of cells you see right you can see mast cells you can see macrophages you can see plasma cells right these are very good at fighting off infections so why would I want one of the functions of aerial are to be able to defend against microorganisms why why is that an important function for areolar well the question is where do you find aerial are in many cases you find it underlying in epithelium right for example this is a simple cuboidal epithelium why would I want right underneath the simple could grow up with them on the basal side to be able to fight off against infections well because that epidermis separating one environment from another environment and that environment possibly can have infectious microorganisms so if I'm up here right and they say this is the lining of my large intestine okay and that's a bacteria right there all right and the only thing separating that bacteria from getting into my blood down here in the connective tissue is this simple epithelium well let's say you damage the walls of your intestine right and all sudden now we have a clear path to enter okay your areolar connective tissue well if nothing's gonna stop them all you have to do now is get to the blood and where does your blood go your blood goes everywhere okay you're gonna get sick pretty quickly but the fact okay that we have macrophages present in areolar the fact that we have mast cells present the Magnum the fact that we have plasma cells present prevents what it prevents now okay this from happening hey we're to the point where we can now just eliminate okay these micro organisms before they can reach your blood okay so your body thinks ahead of time okay it doesn't say oh yeah you know I've built that episode pretty well and I don't think anything's gonna get past that okay your body says well something can get past that I better put cells here just in case something happens to that barrier just in case something happens to that episode all right thanks ahead all right so what are some of the defense cells well we have macrophages okay the ones that have the pseudo pause right here right you also have plasma cells these are the ones I'm gonna prove antibodies for you now you also have mast cells these ones here will release histamine so the idea okay of getting our blood vessels leaky so that what so that white blood cells neutrophils lymphocytes and cinah pills can come out of your blood and then help fight against that infectious microorganism and the fourth function guys okay was because of the cells of aerial or again the ability to store energy in the form of fat is because what is because a areolar has adipocytes areolar has fat cells okay so that's why we call aerial are the prototypical connect tissue hey because it has a pretty good matrix okay it has fibers that can support and bind it has a nice ground substance stick and hold body fluids okay it has all right different kinds of cells that can have a defend against infectious microorganisms and it has adipose sites that can store energy in the form of fat all right so what we're gonna do now inez we go from the pimped-out prototypical connective tissue areolar and we're gonna start and start talking about now all the other different subclasses of connective tissues okay starting off with what starting off with the class that areolar belongs to areolar belongs to connective tissue proper okay so do other tissues yeah you swing it off with that subclass that areolar belongs to and then we'll work away from areolar all right so connects tissue proper has two subclasses it has loose connective tissue and it has dense connective tissue okay so areolar as you kids can see in this slide areolar belongs to loose connective tissue okay lots of cells less matrix adipose is also considered losses as fat tissue okay and reticular connective tissue hey you think about reticular fibers helping support is also part of loose connective tissue in terms of strength these are not as strong as it's a dense okay so this one has less sells more matrix so it's a little stronger so dense regular anything about tendons and ligaments dense irregular you find this for example right in your skin right you also have dense elastic and the walls of your blood vessels like your aorta it has to have be able to snap back or recoil back into shape alright so let's start off with connective tissue proper let's start off with loose connective tissue okay so what would areolar look like right for example on your lab exams alright so we're learning it in lecture but you can always take what you've got from lecture and help you all also with lap all right so if you see this on your lab exam well this here is areolar connective tissue so you can actually see the nuclei in purple these are the nuclei of the fibroblasts these are the cells that make up the fibers right you'll also see here these dark pink thick fibers here well these are the collagen fibers these are the ones that help areolar resist pulling forces that help every LRV this tension okay you also see these these thin black fibers here okay well these are the elastic fibers so if I let go well we can snap back a recoil back into shape because we have these fibers okay what's not shown because they're very fine right are the reticular fibers but there are also reticular fibers present okay in areolar now the next type of loose okay connective tissue is at a post okay so this is probably the most boring slide here we're gonna see the whole term right and the reason why is because when I think about an adipocyte right its entire cytoplasm the majority of it is is a occupied by a fat or lipid droplet and this is where the adipocytes stores the fat okay so the nucleus isn't at the center of an adipocyte the nucleus is right underneath the plasma membrane now based upon once you see here to the right do you think the fat within that lipid droplet stains okay when you put it under a microscope can you actually see no here's a bit of liquid droplet and the fat inside of it does not stain okay but you also can see though in this slide of a fat tissue you also can see the nuclei right here right underneath the plasma membrane okay so ninety percent of the mass consists the fat cells so basically this is just like areolar but what what what function are we really exaggerating or a really fun exaggerating function number four right the ability to store fat they restore energy in the form of fat so very well vascularized guys why okay because you got to deliver nutrients from the bloodstream to the fat cells at the same time she wanted burn fat well then you got to take the fat from the fat cells and bring it back into your blood okay so places you find adipose you find it in the hypodermis right you also find it okay within the mesentery so you find it in the plate part of parts that that kind of anchor and hold your digestive organs into place alright so here's another picture here of that same adipose tissue so here okay we can see that there's some fat tissue also in the breast alright the last type of loose okay connective tissue is reticular connective tissue okay so this is just like areolar but well the only fiber it has in its nucleus are in its matrix is reticular fibers right there are no collagen fibers present here okay there's no elastic fibers present so if you were to take a wild guess okay either you can memorize it if you don't want to but you if you already know what a reticular fibers which is what support right well the job of this is to support hey if you need to support another tissue well you're gonna use particular a connective tissue so here is a slide of the spleen okay so the spleen houses many cells and we can see these reticular fibers okay in dark black these reticular fibers are now supporting the cells present within the scene spleen okay it's also supporting blood vessels okay also present in that recording alright so the second subclass of connective tissue proper is dense connective tissue okay so we have density regular dense irregular and dense elastic okay so before we do density regular okay let's look at dense regular okay and what you can see here okay you actually can see yeah these here represent collagen fibers and they're kind of wavy here right they're not all pointed okay or or flat and straight parallel to one other they are parallel okay with respect to the fact that they are wavy here though right so when I think of dense regular you think about tendons you think about ligaments tendons join what when they done muscles to bones and ligaments join bone two bones okay and easy way to remember that dogs like bones they lick bones so lick'em it yeah you think of bones and ligaments she's joining bones to bones or ligaments joining muscles to bones or attendants so here are those collagen fibers okay oriented horizontally here so would you say that you're pulling on this tendon or ligament right now or you're not pulling on this tendon ligament the fact that I see these collagen fibers look and wavy here you're probably not putting very much tension here okay but the second now you put tension on this tendon or ligament you can kind of expect these collagen fibers all to straighten out hey to run perfectly parallel to one another all right you also see the nuclei here these are the nuclei of the fibroblasts here the cells that make these collagen fibers all right so which way can this okay resist pulling forces okay horizontally or vertically based upon the way and the directionality of these collagen fibers here so if you chose that we can resist pulling forces horizontally you are correct why because that's the way I ever arranged my collagen fibers so I pull horizontally okay we can resist that pulling force now if you start to pull okay in this direction vertically okay you can possibly snap or damage these collagen fibers so picture somebody okay getting hit in the knee and the force is in this direction I won't think of these collagen fibers is snapping okay see do you hear people okay tearing ligaments in the knee for example right it's because the pulling force or the tension was placed in a direction not in the orientation of the collagen fibers all right it's when I think of dense regular you thinking about tendons and ligaments gave very poorly vascularized also right no defense cells no no fat cells so what do these not do well I don't expect the fight against microorganisms I don't expect to store energy in the form of fat okay so if dense regular means that we have regular alignment of the collagen fibers in this case all horizontally what do you think dense irregular is gonna look like okay we're gonna have irregular arrangement of the collagen fibers right so collagen fibers help resist tension but now we have them running in different planes some of them are coming out of the screen some are going behind the screen some are going horizontally some are going oh bleep some are going vertically so now that I have collagen fibers pointed in all different directions what can dense irregular do way better than dense regular you can memorize it or you can just understand it if I have collagen fibers pointed in many different directions what can dense irregular do better than that's regular dense regular in this particular case I don't think there was this point for us okay in this horizontal plane but the fact now that I have collagen fibers oriented in different directions I can resist pulling force in the diagonal plane in a vertical plane in a horizontal plane coming out of the screen going back into the screen okay you can resist tension from different directions now all right and the last type okay of dense regular is elastic connective tissue okay so elastic connective tissue is just like right the ones that we talked about but the elastic fibers outnumber the collagen fibers so they do have collagen so I could resist tension but they have a lot more elastic so what can these do better okay then let's say dense regular or dense irregular well they have the ability to snap back into shape a lot better alright so here are two vertebra these are the bones in your back bone here okay and you can see them here there's this ligament here called ligamentum flavum number ligaments joined bones to bones right and when I saw ligamentum flavum mean I grew up came back in the 80s and 90s right well there was a group called Public Enemy and gay one of the members was called flava flav right it's a ligamentum flavum flavor that's getting old okay but here okay you see a ligament called ligamentum flavum that is made up of dense elastic connective tissue so why would I need let's say collagen fibers here why would I need elastic fibers here so picture for example you're standing straight up and then all of a sudden you need to bend down to pick something up okay what's gonna happen to these two vertebra as now you bend your spine well you're gonna pull the two bones apart from another okay you're gonna stretch this ligament to flavor okay but good we have collagen fibers we're able to then to resist that pulling force as we Bend our back okay but eventually we pick the object up we stand straight up okay so then the two vertebra come back together when you stand up the fact that we have now elastic fibers allows now this ligamentum flavum okay to now snap back into shape as now you stand erect as you stand straight up okay so places where after resist pulling forces and snap back into shape okay you're probably gonna use some dense right elastic connective tissue all right now so that's connected tissue proper and then what well then we also have to talk about right cartilage we have to also talk about bone you also have to talk about blood okay so again these are derived from mesenchyme okay they both they all have cells and they have a matrix right generally speaking a well vascularized I get cartilage is an exception to that right and they're gonna bind to support and then blood is an exception to that function so cartilage and we're not gonna spend very much time on this because there is a skeletal system packet that we're gonna talk all about this okay so we're gonna give you a teaser okay for these three things we're gonna introduce cartilage to you guys in this packet we're gonna introduce bone to you guys in this packet we're gonna introduce blood to you guys in this packet okay just keep in mind hey we're gonna get in more detail when you do the skeletal system for cartilage and bone and we're gonna get into more detail with blood when we do blood when we do the cardiovascular system later on this term okay alright so cartilage is just like areolar but what it's matrix does a very good job at holding body fluids alright so instead of just you know I can hold body fluids I can really hold body fluids when I talk about Carlos 80% of its matrix is water okay so what does that make cartilage do a lot better than areolar well since it's 80% water in its matrix it has the very good ability to resist compressive forces you can kind of think of Carlos as a little shock absorbers basically alright if I'm gonna put something in my shoe right I'm gonna put cartilage there then okay so as I walk in my feet pound against the pavement I have these little okay water pockets in my soles that help resist those compressive forces okay now keep in mind the matrix also has collagen fibers okay not that thick in some cases so I can resist some pulling forces okay but it's ground substance is so well developed that I'm able to hold 80 percent water in my matrix okay because of that I can resist compressive forces pressing forces all right so it's a very firm it's flexible okay now if I'm talking about connecting each popper you think of fibroblasts and fibrocytes okay blast is just an immature version site is a more mature version but if I'm talking about cartilage well now I'm talking about chondroblasts and chondrocytes right and these chondroblasts and chondrocytes they reside in this 80% water matrix this watery matrix okay but carved into that watery matrix okay you have what's called lacunae right so think of this as a cartilage right 80% water and it's matrix all right and carved into this watery matrix I have a space okay and here's another space over here and there's another space in this watery matrix okay and inside that space and again we call that space a lacuna and inside that lacunae you find cells okay so there's a chondrocyte right there for you and there's another chondrocyte over there another chondrocyte over there so if I see a watery matrix if I see lacunae zyv I see these cells inside the lacunae well then note you know you're looking at a cartilage alright and there's three different types of cartilage that are present you have hyaline cartilage ya fibrocartilage and you have elastic cartilage okay so starting off probably the most abundant of the three you have Highline Highline means glassy so here you can see this watery matrix in purple here you got actually here's a lacuna right there okay and inside that of Qunu you see the cell will that cell with this little red nucleus well that there represents a condo site okay so here's lacunae here's that chondrocyte okay and here's that matrix okay 78% water okay so how resist compressive forces I can't really see it here okay but there are thin collagen fibrils present in that watery matrix okay so not can I resist a little bit of compressive forces okay I could resist a little bit of pulling forces also alright so the next type of car is called fibrocartilage okay this is just like Highline but what look at these thick collagen fibers now okay they're so thick that they're actually visible here I couldn't even see them because they're so thin here the collagen fibers are actually visible so I'm combining now two things okay I have a watery matrix that was this compressive forces and now I have now Hall's and fibers that are thick enough to resist stronger pulling forces tension so if I need a place egg resist compressive forces and pulling forces at the same time well you're probably gonna use fibrocartilage now okay so here we see fiber cards for example okay in between your vertebra so if you're standing up there's lots of compressive forces between these bones luckily we have a watery matrix at the same time you bend your backbone what has to happen while you start to separate the vertebra you better have these collagen fibers that help then prevent then these structures from then tearing so we call these intervertebral discs they're between the vertebra okay and these intervertebral discs are made up of a fibril card okay imagine guys if these were made out of hyaline okay and you had thin collagen fibers you came to see him with under a microscope but what happened if we were to bend your back and these vertebra wanted to separate from another you could possibly tear that inter vertebral disc which we a bad thing okay I fail to mention hyaline cartilage is probably the most abundant you find it for example between your ribs you find it in your nose you find it in your joints right when you guys were embryos and even you have bones yet your your skeleton was basically Highline all right so lots of different places you find highly okay intervertebral discs you find them coming to me fiber carbs you find them in your intervertebral discs something called the pubic symphysis that you that you learned in lab you also find it for example in your meniscus in your knee all right different places you find fibro all right elastic cartilage is just like hyaline but what well it has collagen fibers but it has a lot more elastic fibers okay so we know a lot of fibers help recoil or snap back into shape okay so if if I need to resist compressive forces at the same time okay snap back into shape you're gonna use elastic okay so in your ear for example okay so if you flick your ear okay flick this outer part your ear right here okay you notice that it snaps back into shape okay and the reason why is because there's lots of elastic fibers in that outer here okay so again here's my lacunae you actually can see here our chondrocytes inside of these lacunae in this watery matrix all right other places you find that you find the epiglottis for example to really help resist repeated venue all right the third type of tissue okay is bone okay so these have cells these have a matrix came in now we're talking about a cells we're not talking about fibroblasts and fibrous sites or chondroblasts and chondrocytes now we're talking about osteoblasts and osteoclasts immature sites are more mature now in terms of the matrix okay it's not a watery matrix anymore okay anything about your bones is being very solid right you can't bend your bones right and we think about the matrix it's a calcified matrix a very solid matrix containing many calls and fibers right so it's very good at support it's very good at protection now people think of bones as being dead they're not okay people think of Halloween they think of graveyards they think of death these are very much alive all right they do have cells and they're very well vascularized there's lots of blood in your bones and well why because you have red marrow in there right you have yellow marrow that stores fat hey red marrow is actually where blood is produced blood is produced in your bones in the red marrow all right so function supports and protects organs provides levers for attachment for muscles the reason why your muscles contracting it's Shorter's to pull on your bones right stores calcium fat and minerals also red marrow again the site of okay hematopoiesis the sight of blood formation all right so here's a micrograph of compact bone this is the type of bone you would see for example on the outside okay inside of your bones you actually have what's called spongy bone and this is not it right here this is compact alright so here you see these dark okay kind of flat dots these are the nuclei of your osteocytes the cells okay this brown stuff here well this is the very hard matrix this is the calcified matrix okay so I'm not thinking about watery matrix of medium where things can diffuse from your blood vessels to your cells this is solid okay and the reason why okay it's all is because it has to be solid right think of your bones if they were jello right it wouldn't be good we'd be wobbling everywhere every time we walked I don't know if we couldn't even stand up if our bones okay we're watering all right and because of that we're gonna see that we actually carve little microscopic tunnels so that blood vessels can actually pass through this very hard calcified matrix all right actually can see it here okay so this is the we consider a compact bone this is what this stuff is right here so this this cylindrical structure right there is actually right here we call that an osteon okay and these osteons run the entire length of the bone okay and they act as what we call weight bearing colors and we'll get to this when we do okay the skeletal system when we do the bone lecture right but you see here is that in even in the compact bone there are as microscopic tunnels that blood vessels Kate can pass through and why is that because again this is not a watery matrix this is a solid matrix okay and all these cells that you see these little black dots they need to get blood okay and this matrix here is not something that we can just diffuse across we actually have to now carve holes through that matrix okay and then here's a different type of bone we call that spongy bone okay which looks way different under a light microscope and we'll do that again when we now discuss that in the bone lecture all right now the most atypical type of connective tissue again is blood all right so it doesn't bind anything together it doesn't support anything right it's actually a liquid Hey but it does have cells and it has a matrix right so the cells that cellular part and well yes it's derive from mesenchyme okay but it has cells in the matrix so the cells we think about a red blood cells we think of white blood cells we think about platelets okay it does have a matrix and that matrix is called the plasma the fluid component of your blood now the thing about the plasma though it doesn't have any collagen fibers it doesn't have reticular fibers it doesn't have lasting fibers so that's why blood isn't very good at supporting or binding things together its matrix okay in terms of fibers does not have any fibers okay so it does not give mechanical support it does not gay bind things together right so what's the function then well what's its purpose well it's matrix its plasma is mostly water and water is a good solvent things like dissolving in the plasma things like gases gain exact nutrients things like waste okay things like hormones things like cells right so it's basically the transport vehicle for your heart and your blood vessels your cardiovascular system so here's a micrograph okay of blood you can see these cells here that have no nucleus these are your red blood cells these wants to transport oxygen they have a protein called hemoglobin right these larger ones here that do have a purple nucleus okay we consider these ones true cells these are the white blood cells right these are the ones that do something in terms of okay helping you fight against okay infection help you fight against game microorganisms now those are the four tissue types okay so we have connective tissue proper okay we have cartilage we have bone we have blood okay in terms of connective tissues all right so part one of this chapter talked about epithelial tissues right and then part two what you're listening right now talks about connective tissues so much like in lab okay when we did epithelial connective right after that we also talked about skin okay so you guys remember what you wrote down and okay why is skin considered right after you talked about epithelial tissue and connective tissue well first of all it's skin in Oregon yes it is right and skin is an organ that's composed primarily of what well epithelial tissue and connective tissue okay does it have blood yes does it have nervous yes does it have muscle yes okay the blood is Nick did you okay but when I talk about okay the primary tissues that make up an episome hey Oren or membrane or skin we think about epithelial and we think about connective okay so that leads us to membranes right so the three different types of membranes that are out there are continuous membranes mucous membranes and serous membranes okay continious membranes okay is your skin all right mucous membranes well the apical side probably has some type of mucous is probably slick and slippery right these line cavities that are exposed to the outside environment all right so lining your mouth for example that's a cavity in your head expose the outside environment open your mouth okay your throat would have a mucous membrane why because it's exposed to that environment right your trachea your larynx your esophagus your stomach your small intestine your large intestine right your rectum they all have mucous membrane's why because they are lining cavities exposed to the outside environment lining cavities that are not exposed to outside environment are saris memories so lining your pleural cavities the cavities that house your lungs lining your peritoneal cavity the cavity that houses your digestive organs lining the pericardial cavity right that houses your heart okay cavities not exposed to that environment those are lined with Sarah's memories you guys remember so Rossa okay visceral cirrhosis of parietal serosa well there you go okay you guys remember what type of epithelium we're gonna find in this membrane slippers Sicari pus Thackery I did it again slick and slippery well simple squamous epithelia smen brea ghin this is a skin right so here's your wavy boundary the first thing should always do when you look at a slide of skin and look at a figure of skin case find the waiver boundary there it is okay above the wavy boundary well that's your epithelial tissue up here this is your stratified squamous epithelia at the dermis right below the wavy bounty to the point we start seeing lots of fat down here well this here is your dermis okay this is a mixture of areolar and dense irregular okay that is your dermis and not part of skin again down here this is your hypodermis okay so I think of a connective tissue okay now connective tissue with a Catania's membrane or you're talking about the skin okay a mucous membrane okay this lines every hollow internal organ that opens to the outside environment okay so if I'm about the respiratory system lining your reproductive system your urinary system your digestive system we have a mucous membrane okay so what do we call mucous because they are all wet and they're moist okay many of them but not all of them okay secrete mucus so I expect a layer of mucus on the apical surface okay of these epithelia so they have an epithelial sheet and right below that you're gonna find connective tissue okay typically areolar now we're gonna give you term guys lamina propria if you hear the word lamina propria we're always referring to the connective tissue underlying a mucous membrane alright so if this is my epithelium on top okay supporting it is a connective tissue again well if this is a mucous membrane if this right here is a mucous membrane well the name we give to that connective tissue there we call it lamina propria okay all right right and the last type of membrane ok consisting of it up at the and connective tissue is the serous membrane okay so these are slick and they're slippery right these are the ones that line the clothes pleural cavities the pair of carta cavities and the peritoneal okay so these are not open to the outside environment right so again they produce a lubricating fluid so if the organs rub against into one another if they rub up against the wall that they're housed in a it reduces friction okay so all of them again consistent layer of a simple squamous epithelium okay supported on the basal side by a thin layer of areolar connective tissue all right so these net last couple slides guys so that was that was connective tissue okay we're not gonna spend very much time on muscle tissue and nervous we are we won't introduce it right now right but later on there is a muscle lecture and there's a there's a okay nervous system lecture okay we're gonna talk in way more detail about what these look like right the first one now is muscle tissue okay whenever think about muscle tissue I think of what I think of movement alright some of these muscle cells that make up muscle tissue are very long for example skeletal muscle cells are long as smooth muscle cells are long and they're so long that we replace the word cell with fiber okay you ever heard of muscle fibers before or they're talking about muscle cells skeletal muscle cells okay so they have a very long shape them okay we're talking about centimeters long instead of micrometers in diameter so if you guys recall okay typical body cell okay it's spherical some that looks like this right and the diameter of a typical body cell is around 50 micrometers okay so small you can't even see with the naked eye we're talking now about a skeletal muscle fiber okay we're talking about something that is long alright not just one nucleus either you have many nuclei okay right underneath the plasma membrane right underneath the sarcolemma now the reason why these are long why they're centimetres to dozens of centimeters in length right is because what well they have to generate a pulling force when your muscles contract what does that mean when muscles contract do these get longer or do these cells get smaller they get smaller okay they decrease their size and when they decrease their length and when they decrease their size what happens well they generate a pulling force right so if this if this muscle was connected to one bone over here and it's connected to another bone over here well one of these bones just moved in a certain direction okay so by having your cells your muscle cells centimeters long well you can make gross movements you can create gross movements of your body gross movement your bones okay imagine if your muscles were only micrometers in length and you said hey check out this I just flexed my arm oh you didn't see it it's shortened by 50 micrometers yeah we need ourselves to be long okay if we're talking about Kate moving our body so that's why these ones are a lot longer in structure determines function so you have different types of muscle cells out there you have skeletal muscle you have cardiac muscle yes smooth skeletal muscle yes you can see here here's one cell here's another cell here's another so here's an unsent they're all running parallel to one another and they're very long we call these skeletal muscle fibers okay and if you notice about skeletal muscle okay besides being long they have striations they have light dark light dark light dark light dark bands right and the reason why is because they have these things called myofilaments they have actin filaments and they have okay they're mate which made that finish through the thin filaments and you have thick filaments which are made up of a protein called myosin okay so these are voluntary control the cells are long and they're striated cardiac muscle these the only ones we don't call fibers okay these are cardiac muscle cells and the reason why the cells aren't that long okay where do you find cardiac muscle the only place you find them are in the walls of your heart that's it okay so what's who's responsible for caught it causing your heart to beat rhythmically right and unconsciously you don't have no any conscience control this is because of cardiac muscles okay you also know that the cells are striated okay they have these light dark light dark striations also all right now let's draw over here a little bit okay showing you the fact that this is a skeletal muscle fiber okay for a cardiac muscle fiber you're looking at something cells that are shorter and they're branched all right so they're not as long this is a skeletal muscle fiber here okay and this here is a cardiac muscle cell instead of having multi million only have one nucleus right at the center again they're striated okay so these ones have would have striations right skeletal muscle okay it's the same thing here okay with a cardiac muscle soft okay you have striations now joining one cardiac muscle cell to another cardiac muscle cell to say there's another one over here alright you have what's called an intercalated disc and right there is the junction between these two cells this is called an intercalated disc okay and present in here you should cite lots of desmosomes which we talked about a in part one of this chapter alright so here you actually can see in this micrograph okay here's one cardiac muscle cell for example joined to another one and here's a desmosomes in dark purple and it doesn't but an intercalated disc I'm sorry okay joining these two cells together and in that intercalated disc you expect to find lots of desmosomes there okay and then our third type of muscle okay is smooth muscle so a smooth muscle you can see there are no striations that's what we call it smooth right so cardiac muscle and skeletal muscle are striated smooth muscle is not alright the cells are really long so we call these smooth muscle fibers just like we did with cardiac muscle all right and what do they do is where you find them typically in the walls of your hollow organs okay so in the walls of your stomach and the walls of your small test and the walls your large intestines walls of your esophagus right your reproductive system glands all right you find or the ducts you file smooth muscle so through the process something called peristalsis right we're able then to squeeze things through the lumen okay of those hollow organs okay so there's no visible striations cells are long no voluntary control find them in the walls typically if your whole organs alright and then the last two slides guys let's talk about the last tissue which is nervous tissue alright so the main component of the nervous organs is a nervous tissue so I think about your brain has nervous tissue your spinal cord has a nervous tissue your nerves have nervous tissue okay and what does this tissue have well it has neurons and it has supporting cells all right so between the two which one of these are we call the excitable cells which one of the two can send electrical impulses along their plasma membranes okay neurons right these are the ones that have that ability to send electrical signals along the plasma membranes supporting cells these are non excitable cells their job is to support the neurons all right so here we see in in purple this red here's the neuron cell body here's its axon right and then surrounding you see these little tiny okay kind of dots reddish dots well these ones are the nuclei of the supporting cells all right so neurons have things like axons and dendrites and axon terminals and neurotransmitters okay the supporting cells are there to help nourish insulate and protect the delicate neurons okay and again just the introduction to that hey we think about communication we think about control here's that here's a diagram of a neuron here's the cell body here are the dendrites here's the axon here the axon terminals and storing neurotransmitters okay so get just introduction we're gonna talk about this when we do the nervous system packing okay and that's it guys okay so that's the the second half of this lecture and we'll see you on the next one alright have a good day bye