Introduction to Neurophysiology

Question 1

What dictates the direction of ion flux?

Answer 1

Ion Concentration Gradients

Question 2

The sign of the membrane potential and the value of the membrane potential

Answer 2

Ion Flux?

Question 3

Draw out Chemical Force, Electrical Force, and No net flux

Answer 3

Chemical Force: Concentration gradient
Electrical Force: Membrane Potential
No net flux: E=59 log[K]0/[K]in

Question 4

Define/Draw out Nernst Equation

Answer 4

Nernst Equation determines the potential at At equilibrium (No net flux)

Question 5

Write out Nernst Equation

Answer 5

Ek= RT/ZF 2.3 log Ko/Ki

R=Gas Constant
T=Absolute Temperature
Z=Valence
F= Faraday Constant

Question 6

When is Nernst Equation used?

Answer 6

Used for determination of equilibrium potentials for any ion (E eq)

Question 7

When is Goldman-Hodgkin-Katz Equation used?

Answer 7

Use for determination of membrane potentials of cells (V m) (Multiple ions)

Question 8

Write out Goldman-Hodgkin-Katz Equation

Answer 8

Vm=RT/zF 2.3 log ###?

Question 9

Write out Ohm’s Law

Answer 9

I=V*G??????

Question 10

What is the best way to determine Vm for any cell and at any time?

Answer 10

Conductance Equation

Question 11

Write out Ohm’s Law for the membrane

Answer 11

I=G (Vm-Eeq)

I=Current for an ion
G=Conductance for the ion
(Vm-Eeq)=Driving force for ion movement

Question 12

What is generated by passive diffusion of ions through channels?

Answer 12

Membrane Potentials

Question 13

Are channels generally specific for a certain ion?

Answer 13

Yes

Question 14

Ionic movement through the channel is dictated by…

Answer 14

The opening and/or closing of a pore