1. Action Potential Terms
Electrochemical gradient: the sum of chemical and electrical forces acting across the membrane,
Resting potential: the charge(-70 mV) of the neuron membrane when the neuron is at rest
Graded potentials (local potentials): changes in the membrane potential that cannot travel far from the site of stimulation, causes a change in neuron charge Na+ gates open due to stimulus and the neuron becomes more positive(-65 mV or higher)

2. Action Potential Terms
Depolarization: any change in the resting potential toward (0 mV)
Local current: movement of positive charges through a membrane
Hyperpolarization: increase of negative charge due to the loss of Na+ (-75 mV or less)

3. Action Potential Terms
Repolarization: the process of restoring the normal resting potential (-70 mV)
Threshold: a depolarization that causes sodium channels to open (-60 to –55 mV)
All-or-none principle: no matter how big or small the depolarization when the threshold is exceeded an action potential will occur
Refractory period: the time it takes from an action potential to a stabilized normal resting potential

4. Action Potential Generation
Neurotransmitters released by presynaptic cell into synapse
Neurotransmitters cause Na+ channels to open on post synaptic cell membrane
Na+ influx causes depolarization and a local current develops
Local current travels through neuron membrane of the dendrites and/or cell body until sufficient depolarization can cause threshold to be reached, area that is first depolarized on the axon is called the initial segment

5. Action Potential Generation
When threshold is exceeded a large scale activation of Na+ channels occurs and leads to rapid depolarization and an action potential is sent down the axon
As the membrane potential approaches +30mV the Na+ channels become inactive and close

6. Action Potential Generation
At the same time K+ channels open and cause it to flow out of the cell decreasing the positive charge to shift the membrane back to resting potential levels
The K+ channels remain open until the cell is hyperpolarized (-80 to –85mV) then they close the sodium-potassium pumps quickly returns the neuron to it resting potential state (now the action potential is over)

7. Class/HW
BYGO’s Pg 461 #11-17
Draw fig (a) label and describe all 8 steps in your own words