Lecture 7: Resting Membrane & A.P.

Question 1

Removing which of the following ion channels from the plasma membrane of a neuron will have the greatest influence on disrupting resting membrane potential

Answer 1

Potassium leak channels

Question 2

Which of the following would be an alternative answer that would also have an influence on resting membrane potential, but a smaller influence?

Answer 2

Sodium-potassium ATPase

Question 3

Diffusion Forces (Chemical Gradients)

Answer 3

Concentration gradient

- Travel “down” concentration gradient

Question 4

Electrostatic Forces (Electrical Gradients)

Answer 4

• Charge based, opposites attract
• During movement of ions across a plasma membrane, charge will develop on either side; this charge opposes further diffusion

Question 5

Electrochemical Forces

Answer 5

= Diffusion Forces + Electrical Forces

Question 6

Equilibrium potential (Eion)

Answer 6

membrane potential when electrical and chemical forces are equal, no further movement occurs (≠ resting membrane potential)

Question 7

Equilibrium Potential = ENa+

Answer 7

+66 mv

Question 8

Equilibrium Potential = EK+

Answer 8

= -91 mv

Question 9

what is used to calculate equilibrium potential?

Answer 9

Nernst equation

Question 10

driving force

Answer 10

[Resting membrane potential, Vm] – [EION]

Question 11

Goldman Equation (or Goldman-Hodgkin-Katz [GHK] Equation)

Answer 11

Takes into account different ion concentrations and permeability

Question 12

what do Cardiac glycosides inhibit?

Answer 12

Sodium-potassium ATPase

Question 13

what ion has greatest permeability?

Answer 13

K+