hey guys so there's been so much request for a video about tissues so I thought I would finally do it now let's get right to it so we'll start right with tissues which as you know are groups or clusters of cells when you have a group of cells you can call it a tissue and that being said a group of tissues would make an organ a group of organs will make an organ system and many organ systems in a human it would be 11 would make an organism so those are structural levels organization moving back to tissues we have four categories of tissues so I'll write out the four categories and then we'll elaborate on each one the first type of tissue that we'll look at is neural tissue the second type of tissue that we'll look at is muscle tissue connective tissue and epithelial tissue there are two types of neural tissue and they are neurons and neural glia neurons neuroglia the role of neurons is to carry important information up to your brain and from your brain back to your body for example if I were to touch something extremely hot the neurons would carry that oh my gosh is hot information all the way to my brain and my brain would send the appropriate signal so instead of keeping my hand here on this burning hot plate my brain will tell my hand my muscles to flinch and I will immediately remove my hand from the hot plate so you can think of neurons as the main player if neurons are the ones carrying all the information relaying it back and forth what's in the neuroglia to the neuroglia are supporting cells the glia are responsible for providing nutrients providing food insulation removal of waste and so many other functions that's pretty much it for neural tissue so moving right along let's talk a little bit about connective tissue within connective tissue we have four types and let's go into the four types and then elaborate on each one the first type of connective tissue one that people so often forget about is blood the next type that we'll talk about is bone next if we have fibrous connective tissue and finally we have cartilage within fibrous connective tissue we have three types the three types are loose dense and reticular in cartilage we also have three types and the three types are highland elastic and fibrocartilage let's go through connective tissue one more time we started with connective tissue in which there are four types blood bone fibrous and cartilage with I realized there were three types elastic Hyland and fibrocartilage fibrous connective tissue also had three types and they were loose dense and reticular in epithelial tissue there are many more there's actually seven types but the easiest way to break it down is to first break it down according to the number of layers in simple athili old tissue we have one layer of cells simply one later in stratified the word stratified comes from the word strata which means layers you can think of the stratosphere which is a layer in the atmosphere simple means one layer and stratified means there are many many many style layers you can think of it as one page of a book and then many many pages on top of each other of a book it's simple we can further break it down into three subcategories the three subcategories are dependent on their shape and the three subcategories are squamous cuboidal and columnar in terms of stratified we can also further break it down into three sub categories all the dependent on their shape again we aren't going to go with squamous cuboidal and columnar let's talk a little bit about the six types and I'll actually draw a picture for each one note that we started with simple and stratified which tell us the number of cell layers so all three of these are going to have one layer of cells first of all squamous I think a squamous like the word scales and scales on a fish are very very flat so squamous means flat simple one layer squamous flat simple cuboidal means that the cells are Q shaped and again one cell layer thick these red spots are nuclei simple columnar again means that it is one cell layer thick but this time they are long and tall like columns on the stratified side all three of these will have many layers but note that with this one I wrote pseudostratified columnar that's the key here sudo means false it's not truly stratified it only looks like it's stratified but really it's just one cell layer thick so be careful for this one which looks a little like this note that it looks like it's many cell layers thick but really it is just one layer of cells making it a false layered columnar pseudostratified clump what's stratified cuboidal and stratified squamous they really are many cell layers things so you can draw this one as many layers of cubes on top of each other with nucleotide and stratified squamous would be many layers of flat cells again simple and strife I tell you the number of layers squamous cuboidal and columnar tell you the shape of the cell it's also important to note that these are six types of epithelial tissue but there's one more the last one is called transitional transitional epithelial tissue is very unique because it is found in very few places in the body clay you will find some within the bladder the urethra and the curators transitional epithelium is special because it looks like stratified cuboidal I'll draw it in to look like stratified cuboidal the special thing that transitional epithelial cells can do is they can extend link in the bladder it would need to expand so the walls get very thin and be able to return to their original shape where the cells become thicker transitional epithelial tissue can stretch expand and return to its original shape and size it looks like stratified cuboidal got the gravity of tissue we finished all seven and I hope this was easier to sort of visualize breaking it down a little bit and let's move on to muscles in muscles we have three types the three types are smooth skeletal and cardiac I'll write them down and then we'll talk about them a little bit more most importantly we have to note where we can find all of these smooth muscle I can find only in the walls of hollow organs for example I can find smooth muscle inside my stomach in my small intestine and also like the walls of my blood vessels on the other hand skeletal muscles can be found virtually anywhere else on your body for example my biceps my deltoids quadriceps muscles in my calf my the muscles that help me smile all of these are skeletal muscles most of the times you'll find skeletal muscles connected to both smooth muscles are deep within hollow organs skeletal muscles are more superficial and connected to bone cardiac muscle can only be found in one place and that one place is inside the heart you do not find cardiac tissue anywhere else only inside the heart let's talk a little bit about another thing like to highlight which is whether or not it's voluntary or involuntary voluntary means that you have control over it and involuntary means you have no control over it scalps and muscles such as in my hands in my arms in my legs my feet these are all voluntary I can tell myself that I want to lift my arms up I can tell myself that I want to flex all of these are voluntary actions that my brain is telling my muscles via the neurons smooth muscle on the other hand within my blood vessels in my small intestine cannot be controlled these are involuntary and cardiac muscle I can't tell my heart to beat faster I cannot slow my heart rate to 20 beats per minute this is also an involuntary to repeat skeletal muscle is voluntary and the other two cardiac and smooth muscle are involuntary which means that they can contract and relax without any of my conscious thought let's do a full review of all the tissues we have neural muffle connective and epithelial within neural you have two types they are the neuroglia supporting cells and the neurons which are the main cells that carry the message within connective tissue we have four types we talked about blood bone cartilage and fibrous within these there were further subdivisions and then we talked about epithelial tissue in at the figlio tissue we divided it into simple and stratified based on the number of layers and then we further broke it down to examine their shape so after we separated them based on layers we examined their shape was it squamous flat was a cube oil like a cube or was it tall and thin like a column vii at the figlio tissue was transitional which looked like stratified cuboidal but it could stretch finally we talked about the three types of muscle tissue we talked about smooth skeletal and cardiac muscle all of which are found in different parts of our bodies and some are voluntary others involuntary that's pretty much it for tissues I know it was a lot but I hope that was really helpful thanks guys