Action Potentials Flashcards
A rapid depolarization is followed by a ____
rapid repolarization
Neuron re-polarizes at about ___ mV
+20 mV
Depolarization is caused by what?
Increase in cytosolic Na concentraion
Typical resting potential is what?
-65 mV
At +20 mv, the Na ____ force is outward while the Na ___ force is inward.
electrical
concentration
At +20 mv Sodium channels ____ to keep pumping out sodium using electrical force.
close
To repolarize what direction does K+ flow?
outward
At +20mv, what direction is the K+ chemical and electrical force?
Both are outward
Once at -65 mV concentration what direction is the K+ chemical and electrical force?
The electrical force is inward but the concentration force is outward.
At -65 mV concentration what happens to the K+ channels?
The K+ channels close
What structure allows for a change in membrane potential triggering an action potential?
Voltage gated channels
What is the threshold for action potential?
-55mV
What is the period in which a neuron is inactive and will remain inactive until the membrane is at resting potential
Refractory period
What is it called when a current enter and spreads throughout the membrane
Electron-tonic conduction
Propagation speed is dependent on what two factors?
mylination and diameter size
Which axon will have a high propagation speed? The one with the larger diameter or smaller diameter?
The one with larger diameter
The Axon hillock originates what?
depolarization
Axon specifically identify what?
Pathways of communication
Sodium channels have two gates ____ and ____
Inactivation gate and Activation gate
At -65mv the sodium inactivation gate is ___
open
At -65mv the sodium activation gate is ___
Closed
At threshold (-55mv) the sodium activation gate is ___
Open
At threshold (-55mv) the sodium inactivation gate is ___
Open
At +20mv the sodium activation gate is ___
Open
At +20mv the sodium inactivation gate is ___
Closed
At re-polarization the sodium inactivation gate ___
opens
At re-polarization the sodium activation gate ___
Closes
What is the function of an action potential?
It is to communicate with other neurons
