Resting Membrane Potential

Question 1

Combination of an electrical gradient and chemical gradient is

Answer 1

Electrochemical gradient

Ions subjected to an electrochemical gradient will move!

Question 2

Explain the membrane potential of a cell

Answer 2

Occurs due to electrical gradient across a cell membrane

Unequal distribution of charges (ions)

Established by ATPase transporters
Measured in mV

Question 3

The membrane potential of s cell can change due to movement of ions which means it is ____

Answer 3

Not constant

Question 4

Explain the resting membrane potential

Answer 4

Special case of steady state balance between active transport and leakage of ions

Question 5

For most cells the resting membrane potential is between what

Answer 5

-20mV and -90mV

Question 6

Resting membrane potential is at a steady state which means

Answer 6

It is not an equilibrium

Question 7

Convention is ____

Answer 7

Inside with respect to outside

Question 8

The membrane potential difference ____ when the membrane potential is depolarizer

Answer 8

Decreases

Question 9

The membrane potential difference ____ when the membrane potential is hyperpolarized

Answer 9

Increases

Question 10

The concentration of K is maintained over time because the system is at a steady state because __

Answer 10

The rate of leakage through leakage channels is exactly balanced by active transport

Question 11

When is a cell not in equilibrium

Answer 11

When it requires constant energy to stay equal

Question 12

Without a K pump what would eventually happen to the cell

Answer 12

K would eventually leak out until the inside and outside are at equilibrium !

Question 13

How can we make K stay inside the cell if we shut off the pump

Answer 13

Make inside negatively charged to attract the K ions

Make the inside negative with respect to the outside

Question 14

The amount of voltage necessary to keep the K inside is called the

Answer 14

Equilibrium potential

Question 15

Explain the equilibrium potential

Answer 15

The membrane potential that exactly opposes the steady state electrochemical gradient for an ion

Question 16

The equilibrium potential follows the convention which means

Answer 16

Inside with respect to the outside

Question 17

How do we calculate the equilibrium potential for any ion at 37degrees C

What is this equation called

Answer 17

Eion = 61/z X log (ion out/ion in)

Nernst equation

Question 18

K+ equilibrium potential is

Answer 18

-90 mV

Question 19

Na equilibrium potential is

Answer 19

+60 mV

Question 20

Ca equilibrium potential is

Answer 20

+122 mV

Question 21

Cl equilibrium potential is

Answer 21

-81 mV

Question 22

Describe independence

Answer 22

The equilibrium potential for each ion is independent of the concentration of the other ions

Question 23

Give an example of independence

Answer 23

The equilibrium potential for K has no effect on the equilibrium potential for Na or Cl

Question 24

What is Na relative permeability (number of leakage channels)

Answer 24

1

Question 25

What is K relative permeability

Answer 25

50

Question 26

What is cl relative permeability

Answer 26

10

Question 27

What are proteins ect relative permeability (A-)

Answer 27

0

Question 28

What does the Goldman equation predict

Answer 28

RMP considering Relative permeability of Na K and Cl The concentrations inside and outside of the cell

Question 29

What is the goldmans equation

Answer 29

RMP = 61 log (Pk [K]out + Pna[Na]out + Pcl [Cl]in --------------------------- Pk [K]in + Pna [Na]in + Pcl [Cl]out

Question 30

What is the RMP of a normal healthy condition

Answer 30

-78 mV

Question 31

What is the RMP of kidney failure elevated hyperkalemic

Answer 31

-67 mV (depolarization)

Question 32

What is the RMP of severe diarrhea (low hypokalemic)

Answer 32

-89 mV (hyperpolarization)

Question 33

What is the RMP of high levels of anti-diuretic hormone hyponatremic

Answer 33

-79 mV

Question 34

What is the RMP of very high Na permeability

Answer 34

+58 mV

Question 35

Where does K ions move when ion channels open

Answer 35

OUT

Question 36

Where is the most K ions

Answer 36

Inside the cell

Question 37

What direction will Na move when ion channels open

Answer 37

IN

Question 38

Where is more Na ions

Answer 38

Outside

Question 39

Where will Ca ions move when ion channels open

Answer 39

In

Question 40

Where are more Ca ions

Answer 40

Outside

Question 41

What direction will Cl move when ion channels open

Answer 41

In

Question 42

Where are more Cl ions

Answer 42

Outside

Question 43

To understand why ions move the way they do you need to consider what

Answer 43

Equilibrium potential Membrane potential of the cell

Question 44

Ion channels allow ions to diffuse across membranes ______

Answer 44

Down their electrochemical gradient

Question 45

When ion channels open the ions always moves to make ____=_____

Answer 45

Membrane potential Equilibrium potential