This is 3.5 types of connective tissue notes. The essential question is, what are the characteristics, functions, and locations of each type of connective tissue? The first type of connective tissue is the loose connective tissue, also called areolar.
It has a spider web appearance. It has a gel-like matrix. Matrix is the extracellular matrix. which is made up of the fibers and the ground substance, and it is the non-cellular portion of the tissue.
And the location of loose connective tissue would be any type of organs have this thin, clear kind of covering around it. That's loose connective tissue. And the type of connective tissue that's found under the skin, under the epithelium, that's also an example of a loose connective tissue.
Functions of loose connective tissues include soaking up any excess fluid, especially during an infection where organs are producing a lot more fluid. Their job is to soak that up. Also, because loose connective tissue contain many white blood cells, they help in fighting off infection. Other type of cells found inside the loose connective tissues are plasma cells, which are responsible for...
Boring. forming antibodies during an infection and mast cells again remember they make histamine during an allergic reaction and they also contain all three of the fibers the collagen fiber the elastic fiber and the reticular fiber one of the first things you notice about loose connective or areolar connective tissue is the numerous fibers running through the tissue You see all of these thick fibers. Remember any of the string-like materials are fibers.
All of these thick ones back here are your cartilaginous or collagen fibers. You also can see the elastic fibers which are the much thinner ones branching and running throughout the tissue. Those are your elastic fibers. Remember that The fibers are not running parallel. They're kind of crisscrossed all over the place.
Another thing you will notice is this cream or the tan color material in the background. That is your ground substance. And you will see different types of cells embedded inside the tissue. One of the ones that you will see are these cells called the fibroblasts. And remember fibroblasts are responsible for making the...
caudalaginous and the elastic fibers. Here is an actual picture of an areolar or loose connective tissue. Again you can see the thick fibers.
These are your collagen fibers. You have the thinner elastic fibers and remember the main difference besides the fact that collagen fibers are thicker than the elastic fibers is that elastic fibers they branch. So all of these thin lines are your elastic fibers.
The material in the background that is that lavender or white color that's your ground substance and then these oval darker purple looking cells are your fibroblasts. And then another type of cells you will see which is a little bit bigger and they're kind of granulated they have a lot of little dots that's your mast cell. The next tissue is the adipose tissue.
What you will notice in the connective tissue is that depending on the tissue we're looking at, the names of the cells are going to be different. So the cells that are found in the adipose tissue will be called adipocytes, which are fat cells, and their job is for storage of fat droplets. Locations where you might find adipose tissue is under the skin. Then you could also find it in the yellow marrow and also you could find it surrounding organs.
The functions of adipose tissues include energy storage. The fat droplets are stored inside the little compartments for use later on. The adipose tissues found underneath the skin is for insulation, which means to keep the body warm. The adipose tissue found under the, surrounding the organs are for protections against any kind of physical damage or trauma. Unlike the other connective tissue, the adipose tissue does not have a lot of non-cellular or extracellular matrix.
And the entire cell is filled with fat. And then because the entire compartment is filled with fat, the nuclei are basically pushed off near the membrane, the cell membrane. So here is another picture of adipose tissue. Notice that entire tissue is made up of individual compartment of adipocytes and that each one of these adipocytes are filled with fat droplets and these dark structures here, those that are pushed off, are your nuclei. And then just these borders that I'm outlining, those are your membrane, the adipocyte membrane.
The next connective tissue is the reticular connective tissue. And the reason for the name is because it consists of reticular fibers. The location of reticular connective tissues are the liver, the spleen, the lymph nodes, and the bone marrow. The function of the reticular connective tissue is it forms the supporting framework for the cells. It could be for, we're talking about the liver, the spleen, the lymph node, and the bone marrow.
So those cells of those tissue are held together by the reticular connective tissue. Reticular connective tissue always reminds me of the Japanese cherry blossoms. The reticular fibers would be the branches of the cherry blossom tree.
And then the actual blossoms would be the reticular cells. Also within, you do have the fibroblasts because they are the ones that make the actual reticular fibers. Then scattered throughout, you also have a few of the white blood cells. cells scattered through. They're like a little bit lighter in color.
Again here's another diagram. The reticular fibers are the actual little branches that you see scattered throughout. You have a bunch of the reticular cells all over. Then the white blood cells or the lymphocytes are slightly lighter in color but they're kind of hard to distinguish.
The last connective tissue we're going to talk about is the dense or fibrous connective tissue. Fibrous connective tissue has lots of collagen fibers that run parallel to one another. This is important.
Collagen fibers is thick so it is very very strong and it is flexible because it does still have a gel-like matrix but it resists stretching. Dense connective tissue is also avascular which means it has no blood supply unlike some of the other connective tissues that do have some blood supply. Locations for dense connective tissue include tendons and ligaments.
The function of dense connective tissue is it gives it a lot of strength without the stretch but still allows for flexibility. Note the two pictures of the dense connective tissue. Because the caudalagenous or collagen fibers run parallel to each other, it actually creates this band-looking appearance. Those are your collagen fibers. The entire tissue is basically covered in collagen fibers.
And then also, these tiny dark structures, those are the nuclei of the fibroblasts. Here is an actual photo of a dense connective tissue. Notice again the parallel running of the collagen fibers, which gives the organ, like the tendon and ligament, strength. And then this lighter color area are your fibroblasts. Because they do not use any kind of staining, you do not see the nuclei very clearly.
But those are your fibroblasts. The 3.5 notes homework, number one, in your own words, describe the appearance of loose connective and dense connective tissue. Number two, how are adipose tissue unique in appearance from the other connective tissues?
Number three, how does the anatomy of reticular connective tissue determine its function?