1. dendrites
cell body
myelin
axon

2. Perkins & Kent (1991)

3. Synapse: A tiny space between the axon of one fiber and the dendrites of another. Neuro-transmitter chemicals that are released into the synapse stimulate the adjacent fiber to fire (depolarize).
Figure The dendrites of one neuron synapsing with the axon of an adjacent neuron . Reprinted from Denes and Pinson, The Speech Chain, 1993, W.H. Freeman & Co.

4. Axon hillock: Action potentials originate here and propagate along the length of the axon.

5. What causes a neuron to fire
What causes a neuron to fire? (The word fire here means generate a spike potential (an electrical pulse) that travels along the length of the nerve fiber – more very soon.
Neurons are stimulated to fire when neuro-transmitter chemicals are dumped into the synaptic space that separates the axon of one neuron from the dendrites of an adjacent neuron. (Neurons can also be stimulated to fire when an experimenter uses an electrode to deliver an electrical stimulus to an neuron).

7. Action potential
Nerve propagation

8. Action Potential
resting potential (~-70 mV)

9. Better Picture of an Action Potential (This one moves.)
Notice that this figure shows a voltage swing from -70 to +30.