1395535

Assume ionic concentrations in the nervous system
of:

[K]_o = 4 mM

[K]_i= 155
mM

[Na]_o= 145 mM

[Na]_i= 12 mM

7. Use the GHK equation (ignoring any contribution by Cl
or the Na/K pump), and assume RT / zF = 58 mV, to calculate the RMP
of a cell when the gK to gNa ratio is:

i) 10:1?

ii) 50:1?   

iii) 100:1?

8. Which of the above permeability ratios most closely
represents the membrane of a neuron at rest (assuming a cell at
rest has an RMP of -70 mV)? Why? [2]

9. Which of the above permeability ratios most closely
represents the membrane of a glia cell at rest? Why?
[2]