MODULE 1
ï‚§ Chapter 2: Altered Cellular and Tissue Biology (Pages: 47-57,68-70, 87-97)
ï‚§ Chapter 3: The Cellular Environment: Fluids and Electrolytes, Acids and Bases (Pages:115-121)
ï‚§ Chapter 12: Cancer Biology (Page: 368)
Cellular Physiology
- Analyze the steps of the action potential.
ï‚§ Resting membrane potential
ï¶ Extracellular is more positive charge (more cations)
ï¶ Intracellular is more negative charge (more anions)
ï¶ Intracellular charge is -70 to -85 millivolts
ï‚§ Voltage gated Na+ channels open & allow Na+ to enter the cell ïƒ voltage inside the cell moves towards zero (depolarization)
ï‚§ 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
ï¶ Na+ channels close
ï¶ 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