Quick electrical charges that move down an axon is called action potential. Action potential is caused by the movement of positive ions going in and out of the axon. The first step of action potential is called resting potential. This is when the more positive ions are on the outside and the inside of the axon had a “net” negative charge. The next step is called depolarization, this happens when an incoming message stimulates sections of the axon. This happens but channels or the axon opening up and allowing Na+ ions from the outside flow into this inside of the axon. The final step is called repolarization. This means that channels open in the axon but K+ ions are released from the axon and the charge returns to normal. Repolarization is what causes the next segment of the axon to depolarize. The flow of depolarization causes sequential depolarization/repolarization and this is what hat causes action potential to move continuously down the axon.
Synapse communication begins when action potential has reached the axon terminal buttons. At this point the NT are in synaptic vesicles that are still inside the axon. Action potential causes these vehicles to release NT into the synthetic gap. Then the NT disperse all over the gap. After that the NT will bind to receptors on the receiving dendrite. The receiving neuron decides whether or not to send it’s own action potential depends on whether the NT message from the axon was excitatory or inhibitory. Excitatory stimulates the action potential on the receiving neuron and inhibitory represses the action potential on the receiving neuron.