Pharmacology: action potentials

Question 1

what is depolarisation

Answer 1

when the membrane potential becomes more +ve

Question 2

what is repolarisation

Answer 2

when the membrane potential becomes more -ve

Question 3

is the resting potential +ve or -ve

Answer 3

-ve

Question 4

describe why the resting potential is +ve or -ve

Answer 4

due to +ve sodium OUTSIDE the cell and -ve protein INSIDE the cell

Question 5

describe the first step in an action potential

Answer 5

a ligand(i.e. ACh) binds a ligand-gated sodium channel, causing them to open and a sodium INFLUX

Question 6

what does sodium influx cause

Answer 6

depolarisation of cell

Question 7

what happens if depolarisation is large enough to trigger threshold

Answer 7

voltage gated sodium channels open and MORE sodium enters cell causing more depolarisation and an action potential

Question 8

what causes repolarisation of cell to occur

Answer 8

potassium EFFLUX

Question 9

what is the refractory period

Answer 9

a short period at end of an action potential when voltage goes below resting potential

Question 10

can an action potential occur during the refractory period

Answer 10

no

Question 11

what is the voltage of the resting potential

Answer 11

-70mV