Intracellular sodium concentration of the motor neuron
A complete motor neuron is removed from a frog and placed in normal physiological saline at 1 AM. The neuron is healthy. At 2 AM, the physiological saline bathing the neuron is removed and replaced with a modified physiological saline. The composition of the modified physiological saline is as follows: its potassium concentration is the same as normal physiological saline; its sodium concentration is the same as the intracellular sodium concentration of the motor neuron; its total concentration of solutes (osmolarity) is the same as normal physiological saline. For this question, ignore any possible effects due to the sodium-potassium pump. At 2:05 AM, the resting membrane voltage of the neuron is -70 millivolts. At 2:06 AM,
A. the value of the Nernst equilibrium potential for sodium ions for the neuron is greater than -20 millivolts.
B. an increase in sodium conductance will lead to a decrease in the amount of intracellular sodium.
C. an increase in sodium conductance will lead to no change in the membrane voltage.