Resting Membrane Potential

Question 1

The resting membrane potential is the difference of _____ inside and outside the cell at rest, and is equal to _____

Answer 1

electrical charge; -65 mV

Question 2

What are the 3 key components of the RMP?

Answer 2

Neuronal membrane, fluid inside/outside of cell, ion channels in neuronal membrane

Question 3

Ion channels are a form of _____ transportation, while ion pumps are a form of ______ transport.

Answer 3

passive; active

Question 4

______ and _______ and the two forces involved in establishing the RMP.

Answer 4

Diffusion, electrostatic force

Question 5

Ion concentrations being in equilibrium inside/outside of the cell is known as ______, while water concentrations being in equilibrium is known as _______

Answer 5

ionic balance; osmotic balance

Question 6

What does the Nernst equation calculate?

Answer 6

Ionic equilibrium potential

Question 7

A small change in ion concentration has what effect on Vm?

Answer 7

large change in Vm

Question 8

What is the Eion for K+?

Answer 8

-80 mV

Question 9

How does the Goldman equation differ from the Nernst equation?

Answer 9

It takes multiple ions into account when calculating Vm.

Question 10

What is the rate of Na+ ions into the cell compared to K+ ions out of the cell?

Answer 10

3:2 or 1.5x

Question 11

What is the function of Na+/K+ pumps?

Answer 11

establish and maintain the concentration gradient

Question 12

What is depolarization and what causes it in the cell?

Answer 12

A change in Vm from resting value to a less negative value; Na+ ions entering the cell

Question 13

Which cells are responsible for K+ spacial buffering?

Answer 13

Astrocytes

Question 14

What causes the rising and falling stages of the action potential?

Answer 14

Influx of Na+, efflux of K+

Question 15

How are Na+ channels gated?

Answer 15

Voltage (-40 mV)

Question 16

What causes the refractory period after the action potential?

Answer 16

Na+ channels are blocked and cannot be reactivated.

Question 17

What happens if the depolarization threshold isn’t reached?

Answer 17

No action potential occurs

Question 18

The ___ gate of an Na+ channel opens when the membrane depolarizes, the ___ gate closes when peak Vm has been reached

Answer 18

m; h

Question 19

How does myelin increase the speed of action potentials?

Answer 19

It insulates the axon and reduces ion leaks.

Question 20

What is the term for the AP “skipping” from one Node of Ranvier to another?

Answer 20

Saltatory conductance

Question 21

_____ is the process genetically modifying animals to add light-activated ion channels, and uses the protein ______

Answer 21

optogenetics; channel rhodopsin