I've run dr. Mike here let's talk about the four tissues of the body now your body's made up of 30 trillion cells of these cells there's around about 200 individual cell types if you're to group these cells in accordance with their function what you get are the four tissues of the body now these four tissues include nervous tissue muscle tissue epithelial tissue and connective tissue so let's have a quick run-through of each one if we start off with nervous tissue what we're talking about here is that of the nervous system so this is made up
of neurons and glia now glia is greek for glue they're the supporting cells of the neuron there's many different types oligodendrocytes Schwann cells ependymal cells astrocytes these are all different types of supporting cells of the nervous system and in the functional cell of the nervous system the cell that allows for communication to occur this is the primary function as you can see of nervous tissue they're called neurons now these individual cells coming together forming the functional tissue forms the brain forms the brainstem forms the spinal cord and also forms the nerves that come out in
a way and also the nerves that come back in of the brain there's 12 pairs of nerves that go out in the way and back in there called the cranial nerves I've done a video on that and we've got the spine with the spinal nerves as well so this is nervous tissue when we look at muscle tissue muscles allow for movement they allow for us to be able to do something there's three different types we've got cardiac muscle this is the muscle that makes up the heart we've got skeletal muscle this is muscle attached to
bones allows us to be able to move our skeleton and we've got muscle that lines our hollow organs such as the organs of our GI tract even the organs of our urinary tract such as our urethra and you Rita for example or the reproductive system these muscles smooth muscle like I said they're called lining the hollow organs they allow for contraction and relaxation to move products through if we're talking about that of our gastrointestinal tract allows us to move foodstuffs or fecal material through in a process called peristalsis so again muscle tissue therefore movement three
different types cardiac skeletal and smooth move on to epithelial tissue epithelial tissue forms boundaries between environments so for example you've got epithelial tissue that lines your skin separating the outside world from the inside world of your body you've got epithelial tissue of your kidneys you got epithelial tissue of your lungs you've got epithelial tissue anywhere in which those two separate environments empathy Lia sets that boundary now sometimes you want to boundary and allow things to go back and forth sometimes you set a boundary where you don't want anything to go back and forth this is
still the function of epithelial tissue and the individual epithelial cells but you can have epithelia in different shapes and layers so for example you can have simple squamous epithelia so simple means one layer so if you have simple epithelium it's just a single layer of cells if it's Squamish squamous it means they're squish like pancakes you can have stratified squamous that means they're stacked on top of each other you can have simple cuboidal shaped like cubes or you can have simple columnar for example you can also have pseudo stratified where it looks like there's multiple
layers but there's only just one layer or you can even have transitional epithelium where it starts as one type and turns into another type for example if it's flat in one layer it wants things to go through such as diffusion to occur you're gonna find this in your lungs where we want gases to exchange stratified squamous where there's multiple layers well we don't want anything to go through so this is going to be a protective layer such as our skin when you've got a bigger cell in epithelial it that means there's going to be contents
of the cell organelles sub cellular structures for things to happen that means these cells are going to produce something so that means those are the cuboidal and columnar are going to produce things and they're often the mucous secreting cells or even the cells that make up glands of the body all right last one this connective tissue you can see connective tissue supports protects and bonds and there's heaps of different types of connective tissue bone is connective tissue tendons are connective tissue fat cells are connective tissue and even blood is connective tissue sometimes connective tissue can
be solid semi solid or even liquid so then what makes connective tissue connective tissue well connective tissue is made up of gels and fibers okay so the gels are going to be think of jelly for example it's what you embed everything in it's like the concrete for example and fibers are what you put inside of that gel to change the consistency you could put elastic things in that gel to make it bendy and stretchy you could put very solid things in that gel to make it very strong and immovable this is how we go from
having bone or blood it it just depends on the types of gels and fibers embedded in so this is a quick run-through of the for tissue types of the body
