Cell Membrane Potential Lab Report

Based in our experiment, we observed that an increase in the extracellular concentration of K+ increases the membrane potential of the crayfish muscle fibers thereby depolarizing these fibers. This process occurs because the ratio of K+ extracellular to intracellular was manipulated by adding KCl to the solution surrounding the muscle fibers. By increase the extracellular concentration, the K+ ions rushed inside the cell instead of their usual rushing outside. The movement of K+ ions inside the cell made the muscle fibers gain a positive voltage since there will be a change in equilibrium potential for K+ into a more positive value thereby making the membrane more positive.

The calculated expected voltages compared to the experimental recorded potentials provided with different values. [ADD values]The experimental recorded potentials showed a higher depolarization than the

However, the differences in their values could be due to the permeability of muscle fibers to other ions present in the solution and in the fiber- Cl- and Na+ ions. These ions have their own driving forces and equilibrium potentials that affect cell membrane potential. In addition, the use of the Goldman- Hodgkin-Katz equation may have provided with a more similar value to the recorded one since this equation looks at the permeability and concentration of Na+ and Cl- ions not just K+ ions.

While these trends between calculated and recorded are similar yielded similar results, there may have been possible sources of errors. During the experiment, the volume of KCl solution may have differed or not been the exact value, and the dissection of the crayfish may have caused damage to the muscle fibers or release of muscle fibers into the solution affecting conductivity. Moreover, since the experiment was performed through opening the muscle fibers, this may have caused a higher increase of mitigation of