MODULE 1  Chapter 2: Altered Cellular and Tissue Biology (Pages: 47-57,68-70, 87-97)  Chapter 3: The Cellular Environment: Fluids and Electrolytes, Acids and Bases (Pages:115-121)  Chapter 12: Cancer Biology (Page: 368) Cellular Physiology - Analyze the steps of the action potential.  Resting membrane potential  Extracellular is more positive charge (more cations)  Intracellular is more negative charge (more anions)  Intracellular charge is -70 to -85 millivolts  Voltage gated Na+ channels open & allow Na+ to enter the cell  voltage inside the cell moves towards zero (depolarization)  In order for action potential to be successful, it has to depolarize by 15-20 mV (threshold potential) to reach -55 to -65 mV  Repolarization – negatively restored back into cell to -70 to -85 mV  Na+ channels close  K+ channels open  Refractory period – time which cell membrane resists depolarization (occurs during most of the action potential)  Absolute refractory period – membrane will not respond to any stimulus  Relative refractory period – occurs when membrane is repolarizing, will only respond to a very strong stimulus  Hyperpolarized – when resting membrane potential is > -85 mV. Less excitable d/t greater distance btwn resting membrane potential & threshold potential  Hypopolarized – resting membrane potential is closer to 0, e.g. -65 mV. More excitable b/c resting membrane potential is closer to threshold potentia