action and resting potential

action potential definition

the electrical trigger that passes along the axon and stimulates the neurone to activate and release neurotransmitters as a result of synaptic transmission

resting potential definition

the difference in electrical potential on each side of the cell membrane while the neurone is at rest

resting membrane potential and polarisation

- the inside of a neurone is negatively charged and the outside is positive
- there is 10x as much sodium outside the membrane as inside and 20x as much potassium inside the membrane as outside
- the membrane is semi-permeable (has sodium-potassium gateways)
- there is an operating sodium-potassium pump which regulates the equilibrium between potassium and sodium levels inside the membrane

action potential

when the message is sent from the axon of the neurone and then neurone becomes depolarised

depolarisation

- sodium channels open up
- Na+ floods inside membrane
- the inside becomes positively charged as it contains sodium and potassium which are both positively charged