Chapter 2 - Electrical Signals of Nerve Cells Flashcards
What is the resting membrane potential?
Between -40mV to -90mV
Explain the term: concentrational gradient.
The difference in concentration across a membrane. A bigger difference creates a stronger force to equalize.
Explain the term: electrical gradient
The difference in voltage across a membrane, as caused by an uneven distribution of kations/anions.
What is the equilibrium potential?
The equilibrium potential is the membrane potential at electrochemical equilibrium.
In the case of nerve cells, what is the electrochemical equilibrium?
When there is an exact balance between the opposing forces of concentrational gradient and electrical gradient.
Give the Nernst equation?
Ex = (58/z) log ([X]out/[X]in)
What does the Nernst equation do?
It gives you the equlibrium potential for a specific ion.
What does the Goldman equation do?
It gives you the membrane voltage by calculating the equilibrium potential for all the ions present based on their concentration and their permeability.
Why does the diameter of an axon enhance propagation speeds?
It decreases the internal resistance to passive current flow.
If an action potential has plateaus during the falling phase, what does that tell you?
This normally happens as a result of Ca2+ ion channels.
If an action potential has an especially long-lasting undershoot, what does that tell you?
Long lasting undershoots usually result from additional types of K+-channels.
