The basics of neurons

Neurons have three parts to them, the soma, dendrites, and axons. The soma of a nueron is its main body, containing the cells organelles. Radiating out from the soma is the dendrites, where neurons receive signals from other neurons. Dendrites may receive either excitatory or inhibitory signals This transmission of signals is usually through the passage of neurotransmitter between the synapses of dendrites and axons. However, sometimes neurons also pass direct electrical signals through strcutrues called gap junctions. Axons are what the neuron will send a signal through. At the end of the axon is the axon terminal, where neurotransmitters are stored and ready for release. Axons almost always reach to another neurons dendrites, however there are cases where they reach to somas and even sometimes other axons.

In order for a neuron to release neurotransmitter from its axon terminal, it must produce an action potential. The action potential is caused by receiving enough of an exitatory signal at its dendrites. These signals are called graded potentials and will deteriorate over time. If enough graded potentials sum, the cell will release an action potential down its axon and release neurotransmitter to the next neuron. Action potentials are always the same strength, there is no variability to them like with graded potentials. Once they exist, they exist and travel down the axon. Of course while traveling some of the charge may leak out of the axon itself. This is prevented by having thicker axons or by the presence of a myelin sheath over the axon.