Resting Membrane Potentials

Question 1

What are the Basics Principles of Electricity?

Answer 1

Like charges repel each other and oppositely charged substances attract each other

Question 2

What creates and electrical potential
or potential differences?

Answer 2

Separated electrical charges create an electrical potential
or potential differences, because it refers to the difference in the amount of charge between the two point

Question 3

What is Resting Membrane Potential?

Answer 3

• Potential difference across the plasma membrane (i.e., between the intracellular and extracellular environment)
• The inside of the cell is negatively charged relative to the outside

Question 4

What are the Values of Neuron resting membrane potential (generally)?

Answer 4

Neuron resting membrane potential is generally between
-40 and - 90 mV

• Holds steady unless changes in electrical current alter it  in this case, the cell is no longer “resting

Question 5

What is the Major Ion Distribution inside and outside the typical neuron?

Answer 5

Question 6

What does Resting membrane potential depend on?

Answer 6

1. Differences in ion concentrations between the intracellular and extracellular environment
2. Membrane permeability to these ions

Question 7

What is happening?

Answer 7

No membrane potential. There is an equal number of positive ions in each compartment

Question 8

What is happening Here?

Answer 8

1. Potassium channels open, and K+ diffuse on their concentration gradient, creating a net positive charge in compartment 1 and a potential difference between the
   compartments.
2. Movement of K+ has created an electrochemical gradient. If the movement of K+ due to the concentration gradient is greater than the flux due to the membrane potential, K+ will continue to flow into compartment 1 and the potential difference will increase.
3. Eventually an equilibrium potential will be met in which the two fluxes become equal in magnitude but opposite in direction

Question 9

What are Ion Leak Channels?

Answer 9

• Allow ions to diffuse (leak) through the membrane – specific to certain ions and always open
• Movement through ion channels does not require ATP

Question 10

Ion movement across the membrane is in a balance between Concentration potential and Electron potential. What are they?

Answer 10

Ion movement across the membrane is in a balance between:

Concentration potential –
ions want to flow down their concentration gradient

Electrical potential –
ions want to flow towards the opposite charge

Question 11

What is Equilibrium potential?

Answer 11

the membrane potential when the concentration and electrical potential of an ion are equal and opposite in magnitude

Question 12

What is the role of the The Na+/K+-ATPase pump?

Answer 12

The Na+/K+-ATPase pump establishes and maintains the concentration gradient

The (-) membrane potential is maintained by the greater efflux of K+ (due to greater membrane permeability).

Question 13

When is Stable, negative resting membrane potential achieved. What is teh difference in Permability between K+ and Na+?

Answer 13