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Current time:0:00Total duration:2:56

Video transcript

in this video I want to talk about oligodendrocytes oligodendrocytes oligodendrocytes are glia of the central nervous system derived from neural stem cells and named from Greek words for cells with a few branches to show the structure of oligodendrocytes let me first draw a few neurons I'll just draw their somas and axons and I'll leave off their dendrites I'll draw the somos for a couple of oligodendrocytes one here and one here and each oligodendrocyte will extend a few processes maybe up to a few dozen processes each toward at the axons of neurons and the structures at the end of these Allegan and recite processes will be the myelin sheath for neurons the handle myelin sheath on their axons and you can see that each oligodendrocytes can be creating segments of myelin sheath for the axons of multiple neurons and the different segments of myelin sheath can be from different oligodendrocytes on any particular neurons axon this material of myelin is composed mostly of lipid which is the same kind of substance that makes up fat so this is kind of a fatty sheath around some of the axons of certain neurons so let's take a little closer look at this over here and what we'll do is we'll kind of cut through the soma and the process and one of these segments of myelin sheath kind of like this and then we're going to look at it end on like we're looking down from the end of the axon so here I'll draw the axon and we've cut it so we're looking at it end on so we're looking down the tube of the axon and the myelin sheath is just the membrane at the end of the process of the oligodendrocytes that's wrapped very thinly around the axon many many many times like a roll of tape and I like to think of these like the rubber coating on a wire kind of insulating the axon and we'll get into how information is transmitted along axons and other video but basically this makes the transmission of information faster and more efficient and the myelin sheath is still connected by the process to the soma of the oligodendrocytes to maintain it so each oligodendrocyte process forms one segment of myelin on an axon and each oligodendrocyte may myelinate multiple axons in addition to this function of creating the myelin sheath oligodendrocytes also appear to influence neurons and other glia and vice-versa through exchange of a variety of substances there are also some variably shaped non myelinating oligodendrocytes in parts of the central nervous system but their function is not yet entirely clear