Resting Membrane and Action Potentials

Question 1

What is primarily responsible for the RMP?

Answer 1

potassium leak channels (permeability to K+)

Question 2

RMP cardiac and skeletal muscle

Answer 2

-80 to -90 mV

Question 3

RMP smooth muscle

Answer 3

-60 mV

Question 4

RMP neuron

Answer 4

-60 to -70 mV

Question 5

Equilibrium potential (E-ion)

Answer 5

membrane potential when electrical and chemical forces are equal; no further movement occurs

NOT EQUAL TO RMP

Question 6

Nernst Equation

Answer 6

61.5/z(charge) + (log [X-out])/ (log [X-in])

Question 7

Driving force equation

Answer 7

RMP - E-ion

Question 8

if larger ion concentration outside cell

Answer 8

log is +

Question 9

if larger ion concentration inside cell

Answer 9

log is -

Question 10

takes into account all ion concentrations and permeability

Answer 10

Goldman equation

Question 11

depolarization

Answer 11

MP becomes less negative (action potential)

Question 12

hyperpolarization

Answer 12

MP becomes more negative

Question 13

Repolarization

Answer 13

MP returns to resting MP

Question 14

increase in permeability of membrane to Na+ via Voltage-gated Na+ channels

Answer 14

depolarization

Question 15

Voltage-gated Na+ channels

Answer 15

open rapidly, delay, and then close automatically to stop other ions entering the cell
***inactivation gate closes, not permitting ions to pass

Question 16

Voltage-gated K+ channels

Answer 16

not leak channels; turn on at peak AP and filter K+ out selectively; stay on too long leading to hyperpolarization

Question 17

Voltage-gated Na+ channels reset; activation closes and inactivation gate opens

Answer 17

hyperpolarization

Question 18

Absolute refractory period

Answer 18

Na+ channels are open or inactivation gate is closed and cannot open; NO AP can be generated

Question 19

Relative refractory period

Answer 19

inactivation gate is open and the activation gate is closed; K+ permeability still high so hyper polarized cell; not all voltage gated Na+ channels are on same level; AP CAN BE INITIATED BUT NEED STRONGER STIMULUS