Consider a neuron with the following ion concentrations:
Ion Extracellular concentration Intracellular concentration
K+ 4.0 mM 125 mM
Na+ 140 mM 13 mM
Cl- 110 mM 11 mM
a. Using $E_x = -(61.5/z)log_{10}([X]_i/[X]_o)$, calculate the Nernst potential for
K+ ($E_K$). Show your work.
b. Similarly, calculate the $E_{Na}$. Show your work.
c. Similarly, calculate the $E_{Cl}$. Show your work.
d. Given that K+ conductance across the resting membrane = 0.367
ms/cm², Na+ conductance = 0.014 mS/cm², and Cl- conductance = 0.180 mS/cm²,
calculate the resting membrane potential ($V_m$) for this neuron. Show all work,
including intermediate calculations for the individual ionic terms.
e. Assume that -60 mV is threshold potential for this neuron. What is the
mV difference (absolute value) between resting and threshold potentials here (i.e.,
$|V_m - threshold|$)?
