1 and 2 Neurophysiology-student (2).pptx

slides

1. Neurophysiology

2. Membrane Potential Difference in electrical charge across a plasma membrane ≠ concentration of ions across membrane Measured in millivolts (mV)

3. Electrically Charged Only At Membrane

4. NA/K ATPase https :// www.youtube.com / watch?v =Q73uJ8WlY_E

5. Leak Channels: K+ and Na+

6. Resting Membrane Potential Higher concentration of Na + outside Higher concentration of K + inside Potential to do work  signals

7. Resting Membrane Potential

8. Equilibrium Potentials ~ -70mV

9. Equilibrium Potentials What is the equilibrium potential created by K+? -90mV -40mV 0mV +30mV +60mV

10. Equilibrium Potentials What is the equilibrium potential created by Na+?

11. Equilibrium Potentials ~ -70mV Q. What’s the equilibrium potential ( E ion ) when P k = 0.9 and P na = 0.1?

12. Resting Membrane Potential Changes

13. Changes in Membrane Potential Resting Membrane Potential = -70mv Depolarization Inside of membrane becomes less negative Graph deflects upward Repolaraization Inside of membrane becomes more negative Graph returns to resting Hyperpolarization Membrane becomes more negative than resting

14. Graded Potential Ligand-gated Na Channel

15. Graded Potentials Like analog signal, they decay.

16. Subthreshold at Trigger Zone

17. Suprathreshold at Trigger Zone

18. Conformation of VG Na Channels Axon Hillock

19. Action Potential All-or-none Digital Signal: 0 or 1

20. Youtube: Action Potential 20 https:// www.youtube.com / watch?v =U0NpTdge3aw

21. Propagation of an Action Potential

22. Continuous Conduction

23. Saltatory Conduction

24. Refractory Periods Ion channels remain close. No AP could be generated.

25. Neural Synapses A small gap between neuron and neuron: Synaptic cleft Electrical signal needs to be transferred to Chemical Signal

26. Synaptic Communication VG Ca channel open to trigger NT release

27. Neurotransmitters Follow principles of protein-based ( lipophobic ) ligand action Can trigger chemically-gated ion channels Can trigger second messenger cascade Can be excitatory or inhibitory, depending on receptor Influenced by drugs and diseases

28. ACh Acetylcholine Excitatory or Inhibitory Locations Neuromuscular junctions ANS CNS Degraded by AChE

29. Glutamate Major excitatory neurotransmitter in CNS Linked to memory and learning

30. NE = Norepinephrine Excitatory or inhibitory ANS (sympathetic) CNS Mood Motivation Alertness NE transporter for reuptake Postsynaptic Membrane

31. GABA = Gamma-Aminobutyric Acid Primary inhibitory neurotransmitter in brain Reuptake into axon terminal and glial cells by GABA transporter

32. Postsynaptic Potentials Excitatory postsynaptic potentials = EPSPs Inhibitory postsynaptic potentials = IPSPs

33. Temporal Summation

34. Spatial Summation

35. Inhibition GABA opens Cl channel

36. Divergence & Convergence