Action potentials

Stimulating a neuron

Stimulus via recptor cells causes ligand gated NA channels to open

NA enters cell via electrochemical gradient

Membrane depolarises to threshold value of -55mV

Depolarisation

Voltage gated NA channels open (at -55mV)

NA enters cell (via electrochemical gradient)

Further depolarisation occurs moving from -55mV to approx. +30mV membrane becomes less negative

Repolarisation

At +30mV sodium channels close and voltage gated K channels open

K rushes out of cell (via Electrochemical gradient)

Causes membrane to repolarise from +30mV to -70mV cause membrane to become more negative

Hyperpolarisation

Due to K channels staying open for longer amount of time before closing

Hyperpolarisation occurs membrane potential become more negative -70mV to approx. -80mV

Restoration

NaK pump restores membrane potential

By moving 3 Na out of cell and 2 K into cell

restoring the resting membrane potentiall at -70mV