What causes the sodium channels to open successively? 7) what happens when sodium moves into the neuron? 8) how does the neuron repolarize after depolarization? 9) how do neurotransmitters play a role in creating an action potential? 10) what is the difference between an inhibitory and an excitatory neurotransmitter? 11) write a summary of what happens for an action potential to fire. this is worth 50 points. hint: start with the explanation of a neurotransmitter.