48.2 Modeling Of The Resting Potential

Question 1

when does K+ diffusion out reach equilibrium

Answer 1

when electrical gradient perfectly matched chemical gradietn

Question 2

equilibrium potential (Eion)

Answer 2

the magnitude go the membrane voltage at equilibrium for a particular ion

Question 3

how to calculate Eion ( membrane permeable to a single type of ion)

Answer 3

Nernst equation

Question 4

the Nernst equation

Answer 4

at human body temp (37ºC)
ion not charge (1+)

Eion= 62 mV(log ([ion] outside/ [ion] inside))

Question 5

Ek= equilibrium potential for K+ is

Answer 5

-90mV

Question 6

the resting potential of a mammalian neuron is somewhat __________than K+

Answer 6

less negative

Question 7

what counters the negative that K+ forms

Answer 7

Na + can diffuse a little across the few sodium open channels

Question 8

under conditions that allow Na+ to cross the membrane more readily, the membrane potential _________

Answer 8

will move towards ENa and not Ek

Question 9

suppose a cell’s membrane potential went from -70mV to -50mV
–what changes in the cells permeability to K+ of Na+ could cause such a shift

Answer 9

decrease permeability in K+
increase permeability in Na+

(Na makes it less negative)

Question 10

If you disabled the Sodium Potassium pump, what change in the resting potential would you expect to see?

Answer 10

sodium potassium concentration gradient would disappear and so would the resting potential