your body is comprised of 30 trillion cells and you can Clump these cells together in regards to their function and they create tissues and there's four tissue types there's nervous tissue for communication there's muscle tissue for movement there's epithelial tissue that creates barriers and boundaries between structures and finally there's connective tissue that wraps binds and holds things together in this video we're going through everything you need to know about connective tissue thank you hi everyone Dr Mike here in this video we're taking a look at connective tissue and we're going to have a look at the function of connective tissue the different types and also the cellular anatomy of connective tissue which we call histology but first let's begin with the function what does connective tissue do foreign so there are five functions of connective tissue that you need to know the first of which is that it protects second is that it supports it also binds it can transport stuff and it plays a really important role in immunity so let's look at these in a little bit more detail I like to put protects and supports together so connective tissue can protect and support various aspects structures Anatomy within our body I want you to think of the skeletal system your skeleton your bones are connective tissue and you've got a skull that protects your brain and you've got the rib cage which protects your heart and your lungs but also supports as well so your bony skeleton supports the weight of your body think about the fibrous pericardium that surrounds the heart it both protects and supports the heart as well and there's many different organs and structures that will have various capsules or structures around them that play both a role in protection and support when we take a look at binding it actually binds and holds things and anchors structures within the body I like to think about the connective tissue within the gastrointestinal tract so think of our small and large intestines the thing that's stops them from being these sausages that don't wrap and bind and hold these things and sort of create these knots is because the connective tissue the mesentery structures that sort of hold it together but also when it comes to binding I want you to think of the kidneys so your kidneys which are sitting relatively high up in the posterior aspect of your abdomen so what we call retroperitoneal they're actually anchored there by connective tissue and without this connective tissue your kidneys would be free floating so it plays an important role in binding and anchoring structures transport so connective tissue includes blood so blood being a liquid is going to be transporting things throughout your body it's transporting red blood cells that contain oxygen and carbon dioxide as well but it's also transporting things that are dissolved in your blood plasma as well so this includes things like ions so electrolytes nutrients and waste as well as well as other various gases that might be dissolved in that plasma so transport and then finally immunity so think about our lymphatic fluids think about our white blood cells our white blood cells are going to be floating through our bloodstream which is part of the connective tissue and it provides immune support so remember never let monkeys eat bananas neutrophils lymphocytes monocytes eosinophils and basophils they're all cells of connective tissue they're cells that are floating through our bloodstream providing us immunity so these are the five functions of connective tissue that you must remember [Music] now some connective tissue can be hard and dense like bone for example some can be semi-solid like cartilage and adipose tissue so fatty tissue and some can be liquid like blood so then the question that you must ask yourself is what makes a connective tissue a connective tissue if they're also very different in regards to the way that they look what are the underlying features that hold them all together so to speak well there's three different things structurally you need to understand that makes a connective tissue or connective tissue these are the fact that they're all made up of cells gels and fibers let's take a look first is let's take a look at cells what are the different cell types of connective tissue so we can basically break these up into the blasts and the sites so any word that ends so has the suffix blast is going to tell you it's an immature cell it's there to help build that tissue so some examples of blasts for connective tissue include fibroblasts osteoblasts chondroblasts and what we call hemocytoplasts so these are the immature cells of connective tissue fibroblasts will tend to create most of the connective tissue proper we'll talk about what that means in a second osteoblasts bone producing cells chondroblasts cartilage producing cells and hemocyteoblasts are blood producing cells both red blood cells and white blood cells this is in an exhaustive list of the blasts but these are some of the most important and most common the second type of cell you need to know are the sites these are the mature cells the ones that when you look at the tissue down the microscope these are the cells that you are seeing so these include cells like adipocytes osteocytes chondrocytes erythrocytes and finally leukocytes so what we have here are fat cells bone cells cartilage cells red blood cells white blood cells now again it's not an exhaustive list of the cell types but these are the most common and most important so remember these are the cells associated with connective tissue what they do is they produce the next two components that we spoke about they release them to create the very specific connective tissue type so I said the three things you need to remember are cells the second is gels now in actual fact the gels have a specific name called Ground substance so what does ground substance do ground substance is the fluid Rich environment that connective tissue components are embedded within it creates the bulk of connective tissue and the gels or the ground substance is sort of like jelly you go to create jelly it's going to have this wobbly base to it but you can put things in it you can put marshmallows in it you could put a whole bunch of stuff in it but the actual environment that all those things are embedded in that's the gel that's the ground substance and it's made up of three things that you should remember these three things include glycosaminoglycans also refer to as gags that's a horrible acronym but it is gags the second is proteoglycans and the third is glycoproteins now this is where students freak out and understandably have a look proteoglycans protein sugar glycoproteins sugar protein what's the difference it's the same thing it's just flip the other way around well one's going to have more proteins than sugars one's going to have more sugars than proteins but the end of the day all you really need to know is that both of these are protein sugar conjugates and importantly what you'll find is that the proteoglycans are going to be bound to glycosaminoglycans together they end up becoming very very hydrophilic they love water and this is the final component of the gels is water is involved here so water loves binding to these two again creating the bulk of that connective tissue environment now there's other examples of glycosaminoglycans that's not one thing it's actually an umbrella term for a range of things they're just polysaccharides they're big long sugar molecules so what are some examples well one of which is hyaluronic acid another is chondroitin sulfite or even Heparin sulfite but there's many types including keratin sulfate and many others but at the end of the day what you need to know is that they bind to these proteoglycans and then they hold on to the water the question you might have is what about the glycoproteins what do they do they're really important as signaling molecules surface signaling molecules cell signaling molecules they play a role in enzymatic reactions and so forth so these are the gels that's part of connective tissue finally the third thing you need to know about connective tissue is they're made up of fibers so there's three fiber types that you must know these fibers include collagen fibers elastic fibers and reticular fibers so what are these fibers so these fibers will provide some of the important structural characteristics of the connective tissue so the way I like to think about it is collagen fibers are like metal bars they're very very strong so they create rigidity they make it a strong tough tissue elastic fibers are real stretchy they give the connective tissue the property that you can stretch it and then when you let go it snaps back to its normal position so it provides elasticity to a structure and then finally reticular fibers they're feather-like looking structures like Network structures they form what looks like could be a filtration process so if you have a look the reticular fibers they look more like that so they provide a network within the connective tissue so what's some examples all right so really tough types of connective tissue think about when you eat a steak right and you end up getting that tenderness sort of collagenous white tissue that you're trying to need just chew choo choo and you can't break it down you can't break it down because it's filled with collagen right and this is tenderness structures these are fibrous structures holding the muscle tissue together but it's connective tissue so if it contains collagen it's really tough if it contains elastic tissue well it's going to be really stretchy and there's a multitude of different types of tissues that you can stretch within the body they can then snap back and then finally reticular so it forms this network-like structure and what you'll find it's often in lymphatic tissue and we know that lymphatic tissue is very important for filtration and playing a role in the filtration process so often you'll find reticular connective tissues in lymphatic tissues and others like the spleen for example so at the end of the day every single connective tissue contains cells gels and fibers the thing that makes one a solid compared to a semi-solid compared to a liquid depends on the cell depends on the gels and depends on the fiber types so finally what I want to look at is the classification the characterization process of all the different connective tissue types [Music] so when you open up your textbook and have a look at the classification processes that we use for connective tissue it looks complex and it is but I'm going to make it simple for you we're going to have a look at the different ways that we can classify all the different connective tissue types so firstly there's three major headings you need to understand for connective tissue first of which is what we call connective tissue proper the second category is supporting connective tissue and then finally you have fluid connective tissue so these are the first three big headings you need to understand so connective tissue proper proper well the way I like to think about this is this is the proper connective tissue this is the stuff that when you think of connective tissue is connective tissue like the stuff that anchors and holds and binds all the organs of your body that type of connective tissue so it binds it holds its supports and so forth that's connective tissue proper supporting connective tissue supports the structures of your body so think about things like bone and cartilage that's supporting connective tissue and then finally this is an easy one fluid connective tissue that's your blood so there's going to be subcategories within each that we do need to understand first of which is under connective tissue proper you can have two subcategories called dense and loose what's the difference dense simply means that the cells the gels and fibers that make up these connective tissues are densely packed together there's heaps of them and they're really densely packed the loose simply means that they're Loosely arranged within that connective tissue now when we look at dents you can have what we call dense regular you can have dense irregular and you can have elastic so let's take a look at these I already told you that the dense means that their densely packed cells gels and fibers densely packed but what does the regular irregular mean well this is easy it's talking about the fibers the collagen the elastic the reticula regular means there placed in an irregular pattern they're placed in a regular pan so they're all facing the same direction for example so they might have their collagen fibers all facing in the One Direction why would you need a connective tissue where all the fibers are in One Direction well it means they need to resist some form of stretch or pulling or tearing force in One Direction so what type of structures might be dense regular well think tendons and ligaments these are the structures that hold bone to bone and muscle to Bone for example and they resist stretching and tearing forces in single planes super important what about dense irregular well probably makes sense now that I explain that it means that the fibers the collagen elastic reticula they're arranged irregularly at what almost seems to be at random now why would you want these fibers arranged in and a regular pattern well because they need to resist pulling stretching and all these tensile forces in multiple directions think about your skin think about the layer underneath your skin because your Skin's the epidermis that's its own tissue type it's not connective underneath that is the dermis and that's connective tissue so that needs to resist stretching pulling and tearing forces from multiple directions so think you're dermis and then finally you have elastic this is telling you that you have densely packed fibers of elastic tissue so this needs to be a connective tissue that must be able to stretch and then recoil and snap back to its normal anatomical position what needs to do that think about the heart the left hand side of the heart it contracts really hard 120 millimeters of mercury worth of pressure pumping blood out into the arteries and those arteries stretch and then they snap back and recall to continually propagate that blood so that means arteries so that's our connective tissue proper dense now connective tissue proper loose I said Loosely arranged what examples are loose well we've got what's called areola reticular and adipose so areola connective tissue it's a loose connective tissue it's Loosely arranged but it's really important this is the type of connective tissue that anchors and binds the Deep organs of your body so think about your gastrointestinal tract all those structures how it's being held together in your abdomen that's areola connective tissue so this is connective tissue that binds and anchors what about reticular I told you that reticular fibers form these networks for filtration and I said they're really important in lymphatic tissue like the spleen so you find this reticular connective tissue in lymphatic organs and then finally adipose this is easy adipose means fat this is the fat tissue of our body so now what we've done is connective tissue proper both dense and loose easy right now let's look at the supporting connective tissue so we've done connective tissue proper let's look at supportive connective tissue this is the connective tissue that supports our body supports the weight of our body for example like our skeleton and our cartilage so let's have a look we'll first just write bone that's the first time and luckily for us there's no subcategories here so just bone that's all you need to remember and cartilage but there's three subcategories of cartilage that you must know these include hyaline what else elastic and fiber cartilage so what do you think about this you might go wait there's elastic there there's elastic there okay this is elastic dense connective tissue from connective tissue proper the cell types here are mainly fibroblast based cells here the this is going to be chondrocyte or conjoblast based cells but both contain High densities of elastic tissue right so while the elastic elastic fibers so while the elastic fibers are common here the cell type is different hence it's a different type of connective tissue so this is how we arrange it differently anyway let's have a look for the cartilage based what's the difference between hyaline elastic and fiber cartilage so hyaline cartilage is very glassy and it lines the ends of bones that articulate it will it's what we call lining articulating surfaces so think about joints shoulder joint elbow joint knee joint hip joint they all contain hyaline cartilage so think about articulating joints elastic cartilage well this is going to be like the ear for example and the epiglottis this is cartilage that can be moved and distorted and bent and pulled and it snaps back to its normal area so the ear and epiglottis and then fibro cartilage this resists compressive forces so think the vertebrae of your spine and also the meniscus of like your knee for example resists compressive forces all right that is our supporting connective tissue now finally we can look at the fluid connective tissue this is easy this is blood and there we go what we've now gone through is everything you need to know about connective tissue if you like this please hit like lever positive comment for me and subscribe tell your friends I'm Dr Mike thank you very much hi everyone Dr Mike here if you enjoyed this video please hit like And subscribe we've got hundreds of others just like this if you want to contact us please do so on social media we are on Instagram Twitter and Tick Tock at Dr Mike tadarovich at d-r-m-i-k-e-t-o-d-o-r-o-v-i-c speak to you soon