N5315 Advanced Pathophysiology Altered Cellular Function and Cancer Module Core Concepts and Objectives with Advanced Organizers

Cellular Physiology 1. Analyze the steps of the action potential. ● Sodium permeability increases, sodium ions move into the cell increasing positivity, depolarization is occurring, action potential threshold is reached as cell becomes more positive, potassium permeability increases, potassium ions leave the cell, repolarization is occurring, resting membrane potential is reestablished. · The action potential carries signals along the nerve or muscle cell and conveys information from one cell to another. · When a resting cell is stimulated with voltage the membrane becomes permeable to sodium. · Movement of sodium into the cell, the membrane potential decreases, moves to a negative or zero is known as depolarization. Depolarized cells are positively charged. · To generate an action potential and the resulting depolarization is known as threshold potential. It happens when the cell has depolarized by 15-20 millivolts. When the threshold is met the cell continues to depolarize with no further stimulation. This makes the sodium rush out of cell causing the membrane potential to reduce to zero and become positively (depolarization). This rapid reversal in polarity results in action potential