Action Potentials

repolarisation

+30mV to less than -70mV sodium voltage gated channels closed - inactive potassium voltage gated channels open potassium diffuses out of the cell

threshold potential

-55mV

Threshold

-55mV initiates action potential some voltage gated channels open sodium diffuses into the cell

depolarisation

-70 to +30mV all sodium voltage gated channels open more sodium diffuses into the cell

resting membrane potential

-70mV need a small change in ion distribution across the membrane before an action potential is defiantly going to occur

two processes occur that end depolarisation

1 . inactivation of the sodium voltage gated channels 2. opening of potassium voltage gated channels

action potentials result from

a rapid change in the permeability of the neuronal membrane sodium and potassium ions the permeability changes as voltage gated ion channels open and close

where is the action potential initiated

axon hillock

action potential

neurons communicate over long distances by generating and sending electrical signal or nerve impulses is a large change in membrane potential from a resting value of about -70mv to peak value of +30mV and back to -70mV

hyperpolarisation

restore potential back to -70mV sodium potassium pump working sodium voltage gated channels closed potassium voltage gated channels closed