|CLASS: BE ABLE TO DRAW and LABEL (West Point Technique) the Action Potential!
Explanations for Each Step of the Action Potential:
a) RESTING MEMBRANE POTENTIAL (RMP): RMP at -70mV. Na+ on outside and K+ on inside of cell
b) DEPOLARIZATION: As depolarization reaches THRESHOLD of -55mV, the action potential is triggered (opening the voltage regulate Na+ gates) and Na+ rushes into cell. Membrane potential reaches +30mV on action potential
c) PROPAGATION: Propagation (which means spreading or moving) of the action potential at 100 m/sec (which is 225 mph). Membrane potential at +30mV
d) REPOLARIZATION: Repolarization occurs with K+ exiting the cell to return to -70mV (i.e., the cell restores itself to RMP)
e) NA+/K+ PUMP: Return of ions (Na+ and K+) to their extracellular (Na+) and intracellular (K+) sites by the sodium potassium (Na+/K+) pump
NOTE: An Action Potential is a substantial depolarization. At homeostasis, the cell is continuosly alternating from positive (depoloarization) and negative (hyperpolarization) charges. When the cell attains threshold (-55mV), the action potential occurs.
CLASS: BE ABLE TO DRAW and LABEL the Action Potential for the Exam