Neuron Communication

dendrites

myelin sheath

nucleus

axon terminnals

node of ranvier

cell body 

   dendrites   nucleus   cell body   myelin sheath    node of ranvier   axon  axon terminals 

schwann cell  

Resting Potential: when the neuron is "at rest" there are no neurotransmitters acting on the neuron. during the resting potential the inside on the neuron is slightly more negative than the outside, which is positive, with a difference of about -70mv Note: At rest the neuron has some K+ (Potassium) outside and some Na+ (Sodium) on the inside. Action potential: when electrical impulses that travel down the axon triggering the release of neurotransmittersNote: GREATER amount of Na+ OUTSIDE (positive) the neuron and a GREATER amount of K+ INSIDE (negative) during rest1. The Action potential begins when a stimulus triggers Na+ channels to open allowing Na+ ions to flow into the cell making the cell more positive. 2. If there is a strong enough electrical impulse a threshold is reached causing depolarization, reversing the charges, making the outside of the neuron more negative and the inside more positive 3. This reversal of charges (peak voltage) causes sodium channels to close and potassium channels to open allowing K+ to flow back into the cell causing re-polarization; Na+ on the outside, K+ on the inside   4. When K+ gates close, the neuron has slightly more potassium on the outside than Na+ ions inside, known as hyperpolarization 5. Finally the neuron reaches a refractory period in which  K+ returns to the inside and Na+ to the outside leaving the neuron at its normal resting state 

Neuron diagram 1

Neuron digram 2

Neuron Communication