1. Chapter 4 The Action Potential

2. Nernst Relation
[ion] out
[ion] in
E = mV log10

3. Goldman Equation
Pk[Ko] + PNa[Nao]
Pk[Kin] + PNa[Nain]
Vm = 60 log10

8. Time Course of Action Potential

12. Injecting Current into Neuron

13. Frequency vs Depolarization

14. Membrane Currents and Conductances

15. Flipping Potential by Changing Conductance

16. Sodium Channel Structure

17. Na Selectivity Filter

19. Depolarization Changes Configuration

20. Polarization Opens Na Channel

26. Question 1
A new monovalent ion, zirconium, is found to be 100 times more concentrated outside than inside the neural membrane. The neuron has channels that are selectively permeable to zirconium. What is the equilibrium potential for zirconium?
+60 mV,
-60 mV,
+90 mV,
-90 mV,
+120 mV,
-120 mV.

27. Question 2
At the normal resting state there is no net current through the membrane. What is the Na/K pump doing?
nothing,
moving ions out,
moving ions in,
moving some ions in and moving others out

28. Question 3
During the action potential, the sodium current is terminated by the sodium inactivation gate. How is the potassium current terminated?
Potassium inactivation gate
b. membrane voltage
c. depletion of potassium ions,
d. it’s not terminated

29. Question 4
When a membrane is “charged” and maintains a voltage across it, most of the ions responsible for the charge are located just adjacent to the membrane. This distribution exists because:
The membrane is sticky for ions,
ions are repelled by the cytoplasm,
ions are attracted to the other side of the membrane,
ions like to accumulate near the ion-selective channels.

31. Patch Electrode Channel

33. Channel Openings

34. Inward Na and Outward K Currents

36. Time Course of Action Potential

41. Propagation

42. Propagation

43. Electrotonic Decay

48. Myelination

49. Nodes of Ranvier

51. Site of Action Lidocaine

53. Density of Channels = Site of Initiation