Neurons

Question 1

is the ECF or ICF more negative

Answer 1

inside

Question 2

hyperpolarising current

Answer 2

moves the MP away from 0

Question 3

depolarising current

Answer 3

moves the MP nearer to 0

Question 4

describe the process of an action potential

Answer 4

1 - stimulus applied
2 - if threshold is reached, voltage gated Na channels open allowing Na into the cell giving it a +ve charge therefore depolarising the membrane
3- at the peak , Na channels close and K channels open reversing the process
4 - step 3 often overshoots therefore NA/ K pump required to restore the resting membrane potential

Question 5

refractory period

Answer 5

recovery period after an action potential has passed during which no further action potentials can fire

Question 6

how does local anaesthetic work

Answer 6

works by blocking Na channels which stops an AP being transmitted therefore no impulses are transmitted

Question 7

nodes of ranvier

Answer 7

interruptions along the myelin sheath of an axon that expose the membrane and allow ion flow to occur