A basic, mulitpolar neuron is shaped, in my opinion, like Bob Marley laying on is back with his arms cut off. The dendrites stick out in a bunch of different directions like his dreadlocks, the cell body is like his head, the axon is like his body, and the axon terminal is like his legs/feet.
Bob Marley: http://rabbiari.files.wordpress.com/2009/04/bob-marley-print-c12152715.jpg
LOL! But in all seriousness, here is how it works out.........
dendrites - Hairlike structure attached to the cell body (soma, cyton, whatever). The dendrites receive neurotransmitters out of the synapse, and process them into a graded potential.
Soma/Cyton - the cell body of the neuron. The cell body contains the nucleus, etc... it receives the graded potential from the dendrites, and then from that graded potential either polarizes or depolarizes, and forms an inhibitory or excititory response, which *could* lead to the neuron firing, which would involve an action potential being sent.
Axon - the long, "stem" part of a neuron. This part of the neuron is insulated by the myelin sheath, which is formed by Schwann cells. The axon itself conducts an electrical impulse, which is the action potential, from the soma, down to the axon terminal. The action potential is an all or nothing phenomenon, unlike the graded potential which can be in varying strengths, hence "graded". The action potential either happens, or it doesn't. Another difference is that the action potential is always electrical in nature, whereas the graded potential is chemical in nature.
Axon terminal, terminal buds - The axon terminal/terminal buds is the end of the cell where it branches off from the axon... Bob Marley's legs. The axon terminal contains vesicle sacs, and MAO enzymes. The action potential travels to this area, and stimulates the vesicle sacs.
Vesicles - Upon stimulation, the vesicle sacs release neurotransmitters into the synapse.
Synapse - the synapse is basically a fluid filled void/gap between two neurons. The neurotransmitters are released into the synapse after the vesicle sacs are stimulated. They then float across the synapse to the postsynaptic cell.
When the auto-receptor on the presynaptic cell is stimulated, it means the presynaptic neuron has released enough neurotransmitters. The neurotransmitters then reuptake into the terminal buds of the presynaptic cell. The unused neurotransmitters are then either returned to the vesicle sacs to be used at a later time (when the neuron fires again) or they are destroyed and broken down by the MAO enzymes.
Glial cells - These cells surround neurons. Their job is to protect the neurons and maintain a homeostatic environment for the neurons, and provide support for them.
· 9 years ago