Question

Dr. Woodley is trying to explain the concepts of resting membrane potential, equilibrium potential, and membrane potential to the students in her laboratory. To do this, she uses a dish of cultured motor neurons so that she can alter the solution covering the cells and she can use a recording electrode to pierce one of the cells and determine its membrane potential relative to the extracellular fluid. She asks you a number of questions before and after she alters the conditions around the cell. The normal media (fluid covering the cells) contains: 145 mEq/L Na⁺        5 mEq/L K⁺                 and 2 mEq/L Ca⁺⁺

and the intracellular fluid contains:

15 mEq/L Na⁺          155 mEq/L K⁺               and 0.0001 mEq/L Ca⁺⁺(12)

1. List the factors that normally account for resting membrane potential. (3)

2. Dr. Woodley then measures the resting membrane potential (RMP) of the motor neurons and monitor that graphically displays the charge indicates that it is -90 mV. What does this tell you about the influence of the ions listed above on RMP? Why would this occur? (3)

She then changes the media so that the new media is still isotonic to the previous media, but it now contains 110 mEq/L Na⁺, 5 mEq/L K⁺, and 27 mEq/L Ca⁺⁺and she asks you the following questions:

3. Has the equilibrium potential changed for any of the ions? If so, which ones changed, and which one did not? (3)

4. Given the changes made to the media, would the resting membrane potential of the cell change? Why? Or why not? (2)

Answer 1

Dear Student ,

Hope you are clear ?