Synaptic Transmission: Neuron Signaling and Neurotransmitter Dynamics

Resting Neuron

-70mV, more Na+ outside, more K+ inside

Depolarization

when Na+ gates open and Na+ rushes IN and neuron becomes +

Repolarization

When K+ gates open, K+ rushes OUT and neuron becomes more -

Hyperpolarization

neuron is "more" negative than at rest and will not immediately fire again

Threshold

the point of no return, enough Na+ gates must open to reach -55, that will trigger the rest of the Na+ gates to open which will depolarize

Peak

Na+ gates close and K+ gates start to open

action potential

a nerve impulse; a brief electrical charge that travels down an axon

resting membrane potential

the electrical charge of a neuron when it is not active (-70mV)

threshold

the level of stimulation (-55mV) required to trigger an action potential

At REST--Where do you have more Na+?

Outside

AT REST--Where do you have more K+ ?

Inside

relative refractory period

A period after the action potential, when a neuron returns to its normal polarized state and will fire again only if the incoming message is much stronger than usual; during hyperpolarization