Ionic Basis of the Action Potential

Question 1

Define Na+ and K+ equilibrium potential

Answer 1

+ Aka the reversal/Nernst potential
+ The membrane potential at which there is no net (overall) flow of that particular ion from one side of the membrane to the other.

Question 2

What equipment is required to record membrane potentials?

Answer 2

\+ Current stimulator
\+KCl filled microelectrodes
\+ Oscilloscope
\+ Axon
\+ Saline solution

Question 3

What is Ohm’s Law?

Answer 3

V = IR

Question 4

What is Ohm’s Law?

Answer 4

V = IR

Question 5

What are characteristics of the action potential?

Answer 5

+ Initial depolarisation must reach a critical threshold

+ Once the threshold is attained, the depolarising upstroke is regenerative

+ The potential depolarised, overshoots zero and peaks around +30mv

+ The response is all or none

+ The potential repolarises from the peak of the overshoot back to the resting level

Question 6

What are characteristics of the action potential?

Answer 6

+ Initial depolarisation must reach a critical threshold

+ Once the threshold is attained, the depolarising upstroke is regenerative

+ The potential depolarised, overshoots zero and peaks around +30mv

+ The response is all or none

+ The potential repolarises from the peak of the overshoot back to the resting level

Question 7

What types of voltage-gated sodium channels are there?

Answer 7

+ Closed (but capable of opening)

+ Closed (and not capable of opening (inactivated))

+ Open (activated)