In this section you'll find an overview of each step. A resting neuron has a negative charge. That is, there are more negative ions inside the axon than outside the axon. In contrast, the fluid outside the axon has a positive charge. Because the outside and inside of the axon have different charges, the axon is said to be polarized.
Neurons release neurotransmitters.
When a neuron is excited or fires , several events take place to create an electrical impulse. Sodium ions, which have a positive charge, enter the axon. This depolarizes the axon-that is, changes the electrical charge inside the axon from negative to positive. This change starts at one end of the axon and continues all the way to the other end. After the neurotransmitters are released, potassium ions flow out of the axon.