9.2.3 - Resting potential Flashcards
What is resting potential?
When the inside of the axon is negatively charged compared to the outside of the axon.
What is the value of resting potential?
-70mV
At the start of the sodium-potassium pump what happens?
Sodium ions are actively transported out of the axon
Potassium ions are actively transported into the axon.
Describe the concentrations of sodium and potassium ions inside and outside of the axon.
Inside: High potassium concentration
Outside: High sodium concentration
What is the ratio of sodium to potassium ions that move in and out of the axon in the sodium potassium pump?
3 sodium ions move out
2 potassium ions move in
After the sodium and potassium ions are actively transported into higher concentrations, what happens?
They diffuse back.
Sodium diffuses back into axon.
Potassium out of axon.
Describe the permeability of sodium and potassium channels.
Most Na channels are less permeable.
Most K channels are more permeable.
More sodium ions move out of the axon then potassium ions move in.
Sodium channels are less permeable however, what does this result in?
No net movement.
Electrochemical gradient in maintained.
