Resting Membrane Potential Flashcards
The resting membrane potential is the difference of _____ inside and outside the cell at rest, and is equal to _____
electrical charge; -65 mV
What are the 3 key components of the RMP?
Neuronal membrane, fluid inside/outside of cell, ion channels in neuronal membrane
Ion channels are a form of _____ transportation, while ion pumps are a form of ______ transport.
passive; active
______ and _______ and the two forces involved in establishing the RMP.
Diffusion, electrostatic force
Ion concentrations being in equilibrium inside/outside of the cell is known as ______, while water concentrations being in equilibrium is known as _______
ionic balance; osmotic balance
What does the Nernst equation calculate?
Ionic equilibrium potential
A small change in ion concentration has what effect on Vm?
large change in Vm
What is the Eion for K+?
-80 mV
How does the Goldman equation differ from the Nernst equation?
It takes multiple ions into account when calculating Vm.
What is the rate of Na+ ions into the cell compared to K+ ions out of the cell?
3:2 or 1.5x
What is the function of Na+/K+ pumps?
establish and maintain the concentration gradient
What is depolarization and what causes it in the cell?
A change in Vm from resting value to a less negative value; Na+ ions entering the cell
Which cells are responsible for K+ spacial buffering?
Astrocytes
What causes the rising and falling stages of the action potential?
Influx of Na+, efflux of K+
How are Na+ channels gated?
Voltage (-40 mV)
What causes the refractory period after the action potential?
Na+ channels are blocked and cannot be reactivated.
What happens if the depolarization threshold isn’t reached?
No action potential occurs
The ___ gate of an Na+ channel opens when the membrane depolarizes, the ___ gate closes when peak Vm has been reached
m; h
How does myelin increase the speed of action potentials?
It insulates the axon and reduces ion leaks.
What is the term for the AP “skipping” from one Node of Ranvier to another?
Saltatory conductance
_____ is the process genetically modifying animals to add light-activated ion channels, and uses the protein ______
optogenetics; channel rhodopsin
