Ion Permeability Lab Report

Understanding ion permeability is vital to knowing how it establishes a membrane potential, and how it eventually leads to the contraction of muscle cells. This was done using crayfish tail muscles. Lateral and medial tail muscles from the tail of a crayfish were excised. These muscles were then placed into solutions with different types of ion concentrations. Usage of different ion concentrations was necessary in practicing how to measure resting membrane potentials accurately. Measurements with an electrode were then used to calculate the change in voltage across the membranes of the muscle fibers in the varying solutions. The prediction made established that the low sodium concentration solution would lower the threshold for the membrane
At naturally occurring levels the K+ concentration is higher inside the cell to maintain its negative potential.(9) An influx of potassium into the cell will cause the net charge in the cell to become more negative, this is the case when there is a higher concentration of extracellular potassium as there was during the experiment. This increase in extracellular K+ results in the increase for permeability of Na which in turn helps depolarize the cell membrane potential.(13) When there is a lower concentration for Na extracellularly this causes the cell membrane to become more positive inside creating a depolarized cell membrane potential.(8) Both Ca and Na have a positive additive effect upon the membrane potential causing a depolarization in the membrane, and decreasing the membrane