1.5

Question 1

Define what resting membrane potential is

Answer 1

Em= potential difference btw the intra and extracellular space when the cell is at rest (btw AP)

Question 2

skeletal m Em?

Answer 2

-90 mV

Question 3

neuron Em?

Answer 3

-70 mV

Question 4

Define what is diffusion potential

Answer 4

Potential difference generated across a membrane when an ion diffuse down its concentration gradient

Question 5

define what is equilibrium potential of a particular ion

Answer 5

transmemb potential difference at which the influence of conc gradient and electrical gradient on the ions movement exacly balance each other
no net movement of the ion

Question 6

how can we calculate equilibrium potential for one ion?

Answer 6

Nernst Equation
E ion= -60x(1/Z)xLog(C1/C2)

C1- intracellular ion conc
C2- extracellular ion con
Z- ions charge

Question 7

skeletal muscle equilibrium potential?

Answer 7

K+ = -94 mV
Na+ = +65 mV
Cl- = -88 mV

Question 8

neuronal equilibrium potential?

Answer 8

K+ = -90mV
Na+ = +60 mV
Cl- = -70 mV
Ca++ = +130 mV

Question 9

which ion will have the greatest effect on Em?

Answer 9

the movement of ions to which the membrane is most permeable

Question 10

hw can we calculate Em with respect to multile ions?

Answer 10

Goldman-Hodkin-Katz equation

Question 11

How does Na/k ATP contributes to Em?

Answer 11

1. electrogenic (the intracellular “loses” 1 positive charge)
2. K+ gradient

Question 12

why K+ stays inside the cell?

Answer 12

the intracellular is more negative, which makes K+ ions stick around the inside of the cell