Question

What effect would increasing the extracellular concentration of have on the resting membrane potential (RMP)?

A) The RMP would become more negative.

B) Increasing extracellular will have no effect on the RMP because of the / pump.

C) The effects are really seen on the generating potential.

D) Increasing extracellular will have no effect on the RMP because it displaces .

E) The RMP would become more positive (less negative).

Answer 1

Increasing the extracellular concentration of Na+ would make the resting membrane potential more positive due to the inward rush of sodium ions, leading to depolarization.

Step-by-step explanation:

If the extracellular concentration of sodium (Na+) ions increase, the resting membrane potential (RMP) would become more positive, or less negative. This is due to sodium ions being higher outside the neuron than inside, and these positively charged ions would rush into the neuron when channels open, due to the concentration gradient and the intrinsic electrical charge of Na+.

The influx of Na+ would thus lead to depolarization, effectively moving the membrane potential closer to zero. The RMP of a neuron at rest is typically around -70 mV. This negative charge inside the neuron is maintained primarily by the Na+/K+ pump and the differing permeability of the membrane to Na+ and K+ ions through leakage channels, with more potassium ions leaving the cell than sodium ions entering.