Question

Let's consider a scenario in which the resting membrane potential changes from −−70 mVmV to +70 mVmV, but the concentrations of all ions in the intracellular and extracellular fluids are unchanged. Predict how this change in membrane potential affects the movement of Na+Na+. The electrical gradient for Na+Na+ would tend to move Na+Na+ __________ while the chemical gradient for Na+Na+ would tend to move Na+Na+ __________.

Answer 1

The options

A. Out, in

B. In, in

C. Out, out

D. In, out

The CORRECT ANSWER IS A.

A. Out, in

Step-by-step explanation:

The voltage across a membrane is known as the membrane potential. Membrane potential is very critical for the conduction of electrical impulses along nerve cells.

Since, the inner region of the cell is negative when views against the outer region of the cell, the membrane potential promotes the flow of positively charged ions (cations) into the cell, and the flow of negative ions (anions) out of the cell. The diffusion of ions across the plasma is stimulated by the membrane—a chemical force (the ions' concentration gradient), and an electrical force (the impact of the membrane potential on the ions’ flow). These two forces works in unity to form an electrochemical gradient.

If the inner region of the cell is positively charged when viewed against the outside, the electrical gradient will promote flow of positively charged sodium ions out of the cell.