Cell Body- the cell’s life support center.

Dendrite- receive information from other neurons and sensory receptors

Axon- carries neuron’s messages to other body areas.

Terminal buttons- form junctions with other cells

Action Potential is a fast electrical charge that travels down the axon. This is caused by the movement of positive ions in and out of the axon. The action potential is an all or nothing effect, it has a very specific trigger value and if that number is not reached it will not trigger the action potential no matter how close it gets; it is either greater than or equal to. The Action Potential goes in steps. It starts at Resting Potential, this is the stage where the neuron is ready to be used and to send out a signal. When the neuron is in Resting Potential there are more positive ions on the outside and the inside has a “net” negative charge. The next step is Depolarization. Depolarization is while the neuron is being used, while the neuron is in Depolarization the channels in the membrane open to allow NA+ ions to enter the axon. The next phase is Repolarization, this is the recharge period. During Repolarization the channels open to allow K+ ions to exit the axon, this causes the next segment to depolarize. The final stage of Action Potential is Flow of Depolarization, this is a doe-see-doe between the K+ and NA+ to prep for the next wave of AP. The Flow of Depolarization returns the neuron to its original state and is ready to do it all again.

The Insulated Neuron:

When a nerve impulse reaches the end of an axon and reaches the trigger value called the threshold, the axon releases chemicals called neurotransmitters. The different transmitters are Serotonin, Dopamine, Acetylcholine, Gamma-aminobutyric acid also called GABA and Glutamate. Neurotransmitters travel across the synapse gap between the axon and the dendrite of the next neuron. The neurotransmitters diffuse through gap & bind to receptors on receiving neurons. Neurotransmitters bind to the membrane of the dendrite. The binding allows the nerve impulse to travel through the receiving neuron. The receiving neuron decides whether or not to send the signal to the next neuron by taking the sum of the signal. If there is more excitatory the inhibitory signals then it will continue down and send the next signal; however, if there are more inhibitors then excitatory then the neurons will not send the next signal and it will not continue down. The reason for this is because we have so many signals flowing through our body all the time, and the nerve cells are connected to thousands of nerve cells and this needs to be controlled and monitored so there is no overload of information.