What the blip do you know - about nerve cells?

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Our nervous system is composed of two main types of cells. One type is called Glia cells. These cells are the maintainence cells which are responsible for "grizzing and oiling" and all other maintainence required for the other type of cells to work properly. There are many types of Glia cells with various "jobs". One of these "jobs" is to encircle Axons (keep on reading to know what it is) with myalin - a fatty substance that is used for insulation. The other type of cells, which most of us know about, is neurons. Neurons are composed of 4 main areas: 1) Soma - cell body. 2) Axon - a "tube" which transmits data from the soma to the next cell. The output section. 3) Dendrites - the "input" section. 4) Synapses - The messege recievers on axons and dendrites. Composed of a presynaptic terminal on the axon and a postsynaptic terminal on the dendrite, with a "chasm" of about 20-50 nanometers between them. The main activity is done in the synapse. Axons and dendrites in mammals are usualy enveloped with myalin, which makes signal transduction better, because it indulates them. Since the signal in Axons and Dendrites is elecricity, insulation helps it move faster and farther. Animals without myalin must have bigger Axons to react faster. When an axon fires, it is called Action Potential, which moves to the next neuron's dendrite and tells him something important happened in the previous neuron. This is the messege the goes in our brain. We are born with a certain amount of cells in our brain, and almost no new cells are born thorought life. There is a phenomenon called sprouting, in which Axons and Dendrites take the place of dead cells. This fact is used in the Hungarian method of treating disabled children. A disabled child is put on a hard plate and cannot move. Since it is painful for him, he moves what ever he can (even just flinch his eyes and moves his fingers). The live sensory part excites the dead motor part, and the live motor cells take the place of the dead ones by the means of sprouting. There are many types of cells (look at the picture to view 3 of them) and they differ by the action potential firing rate, size, form etc. How does an action potential moves from cell to cell? In the synapses there is a substance called neurotransmitter. When an action potential gets to the synapse of an axon, it opens tunnels and allowes the neurotransmitter to go out of the terminal of the axon and enter the terminal of a dendrite via the "synaptic chasm" - and this invokes a rise (or sometimes a decrease) in the potential of the dendrite, hence creating an input for the next neuron. As said, there are many types of cells, and there are many types of neurtransmitters. The variety in the human CNS (central nervous system) is the largest we know of nowdays. This is the picture at large. As usual, any questions, remarks and supplements are more than welcome.