An end-stage renal disease patient has been on peritoneal dialysis at home. Based on his lab work, he regulates the type of solution to infuse into his abdomen

Question

When there is a high concentration of potassium inside the cell (hyperkalemia), the solution infused has a lower concentration so that the potassium ions will diffuse outward. At this point, the cellular membrane is said to be
A)
at equilibrium potential in which no net movement of ions occurs.
B)
charged with high voltage.
C)
filled with positive current.
D)
polarized because of the presence of a negative membrane potential.

Answer 1

Ans:
D

Feedback:

Because of the large concentration gradient existing across the cell membrane, potassium ions tend to diffuse outward. As they do so, they carry their positive charges with them, causing the inside to become negative in relation to the outside. This new potential difference repels further outward movement of the positively charged potassium ion. The membrane is said to be polarized.