Membrane Potentials

Question 1

Fundamental basis for cell signaling

Answer 1

Electrical potentials

Question 2

Intracellular net charge

Answer 2

Negative

Question 3

Whats higher inside and out

Answer 3

Na, Cl, Ca high outside

K and anions inside

Question 4

Establishment of ion gradient

Answer 4

Na/K ATPase pump

Moves 3 Na out and 2 K in

Maintains concentration gradients after action potentials

And electrogenic

Question 5

Factors contributing to resting potential

Answer 5

Ion concentration gradients and membrane permeability

Question 6

Electrical force factors

Answer 6

Increase with quanity of charge and decreasing distance

Question 7

K+ channels example

Answer 7

K+ channels open
K flows in
K flows out
Equilibrium will be reached both electrically and concentration

Question 8

Equilibrium potential

Answer 8

When fluxes because equal in magnitude but opp in direction

When electrical gradient=concentration gradient

Question 9

Na, Cl, and K equilibrium potentials

Answer 9

Na = 60
Cl = -72
K = -89

If concentration changes then gradient changes

Question 10

Hypo and hyperkalemia

Answer 10

Hypo - hyperpolarized because K will flow out of cell

Hyper - depolarized because K will flow into the cell

Question 11

Permeabilty determined by

Answer 11

of open channels in the membrane

K+ wayyyy higher than Na at resting

Question 12

Normal membrane potential

Answer 12

-70 mV

Potassium contributes the most

Question 13

Steps in establishing resting potential

Answer 13

Na/K ATPase establishes

K efflux makes it more negative o nthe inside

Ion flux back into cell through pump to help balance