神经细胞类型简介

in this video I want to introduce the different types of neural cells the word neural or the prefix neuro just refers to the nervous system so that neural cells are cells of the nervous system neural cells work with all the other cell types of the body to produce the amazing range of functions of the nervous system including consciousness social interactions cognition emotion movement sensory perception and regulation of other functions such as circulation respiration and digestion neural cells are divided into two big categories the first are neurons which were traditionally called nerve cells and the second argue now these can also be called neuroglia or glial cells that all means the same thing neurons are named from a Greek word for nerve while Galia are named from a Greek word for glue because they are once thought to do little except glue neurons together the structure of the nervous system is divided into two main parts the first part is mainly made up of the brain in the head and the spinal cord in the spine and this part of the nervous system is called the central nervous system the other part of the nervous system is called the peripheral nervous system and that's made up mostly of nerves these long stringy structures that come out of the brain and the spinal cord and they go all over the body like down into the arms and down into the legs and into every part of the body and we'll cover a lot more detail about neural anatomy in other videos but I just need to bring up the central and peripheral nervous system because the neural cells are divided up differently amongst the different systems calling neurons nerve cells is a little problematic because these structures in the peripheral nervous system called nerves are made up of neurons but they're also contained glial cells and they contain a number of other cells that aren't neural cells at all however you'll often hear people refer to neurons as nerve cells because that was the traditional name for them neurons are found both in the central nervous system the brain in the spinal cord and the peripheral nervous system in the nerves but the different types of glial cells are found only in one or the other most neural cells derived from populations of cells called neural stem cells or neural crest cells and both of those cell types arise early in development in the part of the embryo called the ectoderm most neurons and glia found in the central nervous system are derived from neural stem cells while most neurons and glia found in the peripheral nervous system are derived from neural crest cells now we'll go into a lot more detail about what neural stem cells are neural crest cells in other videos when we cover development of the nervous system most types of both neurons and glia share some structural features of the way their cell is shaped most of them have a main part to their cell called the soma or the cell body that contains the nucleus and most of the organelles coming out of the soma most of these cell types have processes long thin extensions that come out of the soma and the processes of the different neural cells vary a number and in length and thickness and degree of branching because some of them will be unbranched and some of them will have processes that branch sometimes a little and sometimes a lot they will also vary a lot in the terminal structures at the end of their processes and the function of these structures and the processes the function of neurons is to process and transmit information and the function of glia is to support them in a variety of ways there are many structural and functional types of both the neurons and glia and there are large numbers of these cells making up the nervous system there are billions of neurons that form trillions of connections in the adult human nervous system and there are even more glia than there are neurons in subsequent videos we'll go over the most common glia which are astrocytes microglia ependymal cells oligodendrocytes and schwann cells there are also less common glia such as satellite cells and olfactory and sheathing cells but we'll just go over the most common types