Resting potential, active potential and propagating potential

Question 1

Steps of the resting potential

Answer 1

3 Na out 2 K in by NaK pump = more Na out than in, more K in than out = Na diffuses in down electrochem gradient and K diffuses out BUT most Na gated channel closed = Na no in but K out so out more positive than in so membrane = -70mv

Question 2

Describe how action potential works

Answer 2

1. neurone at RP - some K ion channel open, Na ion channel closed
2. energy of stimulus = na ion volt gated open, Na diffuse inside down electrochem grad, inside neurone less negativ
3. change in charge = more na channels open, so more na in
4. when +40mv, na channel close, k ion volt gated channels open
5. K diffuse outside down electrochem grad, inside more negative than outside
6. initially, lots of K diffuse out of axon, inside more negative than usual, hyperpolarisation. K channels close. NaK pump kicks in