after i tell you how to differentiate the six types of connective tissue proper i have 10 practice questions so when you're looking at connective tissue you want to think what fiber types am i seeing what directions are those fibers going in and it can also be helpful to look at the type of cells and the quantity of cells you're seeing so there's three possible fibers collagen elastic and reticular collagen is the thickest elastic is medium and reticular is the finest now i did put colors but the color is going to depend on what type of stain was used to stain the slide collagen and elastic are visible with the most common type of stain that they use as being pink and purple but the reticular usually you can't see it because that requires a special type of stain so looking at the first one that's the easiest that everyone learns very quickly that is adipose you don't have to worry about the fiber types it's just a bunch of fat cells so each one of these bubbles is a singular fat cell and the inside is filled with a drop of fat the biggest problem people have with adipose is that people will see simple squamous and think that it's adipose i'm gonna make a short video about that issue and pin it in the comments once i make it so the tissue next door in the background you're seeing kind of out of focus thicker pink fibers and in the foreground these black looking fibers so this is areolar connective tissue and the defining characteristic of it is that you have these pink collagen fibers and the black to purple elastic fibers randomly arranged in many directions and there's a lot of open space because a reeler is a loose connective tissue as opposed to a dense connective and there's also usually lots of these little black dots which are cells called fibroblasts over here so if you compare these black thready fibers to the fibers that you're seeing in areolar you'll notice that they look more like a net and more like a mesh whereas the areolar ones are very straight now those are the reticular fibers so this is reticular connective tissue and this is the one where you need a special stain to see it now when you're first learning usually the example they show you is a lymph node and in a lymph node you have lots of these circular cells so those circular cells you're seeing are also a hint that this is reticular so all these ones on the top are loose connective tissues because they're not packed as densely they don't have as much collagen if we go down to the bottom now this is a dense connective tissue so if you see the fibers they're kind of stained a light pink this is why you can't rely on color too much because many people would not see that as being pink but you see that the fibers are all going in one direction and these cells are kind of smushed in between the different fiber bundles this is dense regular connective tissue so it's called regular because the fibers are running in one direction next door we have fibers running in many directions so you have some fibers running this way and then this was a bundle of fibers that was kind of coming straight at us and then it got cut so we're seeing like the stumps that have been cut so because these collagen fibers are running in many different directions this is dense irregular and over here now this type of tissue is not very common and all the examples i have ever seen do tend to look pretty much like this you're seeing wavy elastic in the foreground and in the background it's kind of over a bed of pink collagen fibers this is elastic connective tissue not to be confused with elastic cartilage which is an entirely different tissue if you want to learn about cartilage i will pin a link in the comments i have a special video just for cartilage okay so i'm going to show you 10 practice questions and i'm going to give you 10 seconds to think about each question before i explain what the correct answer is and how you should have been able to know what it was okay so you should see that we have fibers going in one direction we only see one fiber type which appears to be collagen because it is pink and sandwiched in between we see fibroblasts and that's how you should know it's dense regular connective tissue i'm not even giving you 10 seconds because i know that you know when you see all these little bubbles all these very thin little bubbles you're looking at adipose okay so you're seeing black fibers that are making a net which lets you know you're looking at reticular connective tissue all right so this very much looks like hamburger meat what you're seeing is fibers going in all different directions that have been cut that's how you know that you're looking at dense irregular connective tissue so you have these black fibers going in all different directions in the foreground and there's kind of a haze of pink in the back that haze of pink is collagen fibers which are out of focus and you're seeing many of these little black circles which are fibroblasts and all of those things should tell you that this is areolar connective tissue okay so i cheated this is not connective tissue this is simple squamous um and this is how people are going to confuse it with adipose because they see lots of open space and circles and they're like oh adipose but what you need to pay attention to is all those little black specks are nuclei um that tells you that this is multiple cells it's not just one fat cell we have multiple nuclei multiple cells so this is many little squamous cells making a circle also you'll notice if you compare side by side squamous simple squamous um this isn't a lung it's not perfect little circles they're kind of irregular circles and if you need more help like i said i'm gonna make a video specifically just about this okay so you're seeing purple little waves those are bundles of elastic and it's over a background of collagen which is kind of out of focus and that tells you that this is elastic connective tissue so this is further away than you've seen it before but even though you can't see the individual fibers you can kind of see the wavy pattern in the background and you've got a bunch of cells here which are smooshed so what you're seeing is fibroblasts smushed in between collagen fibers so this is your dense regular connective tissue people sometimes will see certain types of smooth muscle and confuse it with this i'm going to make up a whole other video about that as well so once again black purple elastic over pink it's elastic connective tissue and lastly are fibers going in all different directions two different fiber types are visible little black specks which are fibroblasts has to be areolar connective tissue Alright, i hope that was helpful have a great day and have fun learning