Presentation is loading. Please wait.

Presentation is loading. Please wait.

Chapter 4 The Action Potential. Nernst Relation [ion] out [ion] in E = 61.54 mV log 10.

Similar presentations


Presentation on theme: "Chapter 4 The Action Potential. Nernst Relation [ion] out [ion] in E = 61.54 mV log 10."— Presentation transcript:

1 Chapter 4 The Action Potential

2 Nernst Relation [ion] out [ion] in E = 61.54 mV log 10

3 Goldman Equation P k [K o ] + P Na [Na o ] P k [K in ] + P Na [Na in ] V m = 60 log 10

4

5

6

7

8 Time Course of Action Potential

9

10

11

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

18

19 Depolarization Changes Configuration

20 Polarization Opens Na Channel

21

22

23

24

25

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? a.+60 mV, b.-60 mV, c.+90 mV, d.-90 mV, e.+120 mV, f.-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? a.nothing, b.moving ions out, c.moving ions in, d.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? a.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: a.The membrane is sticky for ions, b.ions are repelled by the cytoplasm, c.ions are attracted to the other side of the membrane, d.ions like to accumulate near the ion-selective channels.

30

31 Patch Electrode Channel

32

33 Channel Openings

34 Inward Na and Outward K Currents

35

36 Time Course of Action Potential

37

38

39

40

41 Propagation

42

43 Electrotonic Decay

44

45

46

47

48 Myelination

49 Nodes of Ranvier

50

51 Site of Action Lidocaine

52

53 Density of Channels = Site of Initiation


Download ppt "Chapter 4 The Action Potential. Nernst Relation [ion] out [ion] in E = 61.54 mV log 10."

Similar presentations


Ads by Google