Resting potential
D
Stimulus
E
Action potential
What the red line indicates
Depolarization
A
Repolarization
B
Threshold
C
Hyperpolarization
G
Na+/K+ pump
This uses energy to fix the locations of the ions and returns the axon back to resting potential
Na+
Diffuses into the cell during depolarization
K+
Diffuses out of the cell during repolarization
Na+ gates open (increase in Na+permeability)
A stimulus begins an action potential by
-55mV
Threshold
Na+ closed, K+ open
H
Repolarization
K+ channels open, allowing efflux of K+, and cell becomes more negative
Hyperpolarization
K+ gates shut too slowly, causing the membrane to get too negative