Potential Questions on Action Potentials

Question 1

resting phase

Answer 1

activation gate is closed

inactivation gate is opened

Question 2

activation phase

Answer 2

activation gate opens during initial depolarization

Question 3

inactivation phase

Answer 3

inactivated gates closes rapidly after activation phase

cannot be moved until membrane potential returns to near resting phase

Question 4

during the relative refractory period, action potentials may be

Answer 4

initiated but requires a stronger stimulus

Question 5

hypokalemia is worsened by

Answer 5

high salt diet, sugar, alcohol

example of membrane potential dz is hypokalemic periodic paralysis (HypoPP)

dips in blood K levels, drops in blood K triggers events, but blood K levels are normal between attacks

membrane hyperpolarized, harder to reach threshold, repolarization occurs more quirckly

Question 6

hyperkalemia dz

Answer 6

hyperkalemic periodic paralysis

excess K in blood, unable to metabolically compensate

long action potential and absolute refractoru periods are lengthened.

sx managed by mild exercise, K-wasting diuretics, glucose consumption

caused by a gene mutation

Question 7

ion in > ion out, log will be

Answer 7

negative

Question 8

ion in < ion out, log will be

Answer 8

positive

Question 9

if ion in = ion out, log will be

Answer 9

0

Question 10

always take into account ion charge if it is

Answer 10

+/-

Question 11

hyperkalemia moves the resting membrane potential to

Answer 11

closer to 0, less negative

Question 12

hypokalemia moves the resing membrane potential to

Answer 12

more negative (away from 0)

Question 13

insulin and beta catecholamines enchance

Answer 13

cell uptake of K by stimulaiting Na/k ATPase (with cAMP for cat)

Question 14

a catecholamines impair cell uptake by

Answer 14

inhibiting NA-K ATPase