Dr. Norris tries to explain the nervous system….

1. Dr. Norris tries to explain the nervous system…. The OLLI Version

2. Anatomy (Construction) Physiology (Function)

3. CNS PNS OUT IN

4. CNS PNS Afferent (in coming) Efferent (out going)

5. Sensory input Sensor Integration Motor output Effector Central nervous system (CNS) Peripheral nervous system (PNS)

6. Neuron

7. Dendrites Cell body Axon Neuron

8. Direction of signal Neuron

9. Neuron 3 types of Neurons

10. Sensory Neuron

11. Association Neuron

12. Motor Neuron

13. Sensory input Sensor Integration Motor output Effector Central nervous system (CNS) Peripheral nervous system (PNS)

14. Nervous Systems

15. Nerve net A little more concentration

16. The vertebrate way

17. A Physiology (Function)

18. The Action Potential

19. Cell Membrane

20. Membrane with gates

21. Electrical potential across the membrane Microelectrode –70 mV Voltage recorder Reference electrode

22. Resting State OUTSIDE + + + + + + + + + + + + + + + + + + + + + + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - INSIDE Cell membrane neuron

23. Resting State Potassium channel Activation gates OUTSIDE Na+ Plasma membrane INSIDE Sodium channel Inactivation gate K+

24. Depolarization OUTSIDE Na+ Na+ K+ INSIDE

25. Rising phase of the action potential OUTSIDE Na+ Na+ K+ INSIDE

26. Falling phase of the action potential OUTSIDE Na+ Na+ K+ INSIDE

27. An action potential is propagated

28. Action potential Na+ An action potential is generated as Na+ flows inward across the membrane at one location. Action potential K+ Na+ K+ The depolarization of the action potential spreads to the neighboring region of the membrane, re-initiating the action potential there. To the left of this region, the membrane is repolarizing as K+ flows outward. Action potential K+ Na+ K+ The depolarization-repolarization process is repeated in the next region of the membrane. In this way, local currents of ions across the plasma membrane cause the action potential to be propagated along the length of the axon.

29. The Action Potential

30. Vertebrate Neuron

31. Invertebrate Neuron – No myelin sheath

32. Action potential propagation down the axon Schwann cell Depolarized region (node of Ranvier) Cell body Myelin sheath Axon Saltatory conduction

33. Invertebrate Vertebrate

34. Saltatory conduction Allows for very rapid transmission of action potential Vertebrate

35. Escape Neurons or Giant axons

36. Earthworm in cross-section Nerve cord

37. Earthworm nerve cord Giant escape axons

38. Myelinated neuron Schwann cells

39. Multiple sclerosis

40. Passing the signal on – The Synapse

42. Synaptic vesicles containing neurotransmitter Presynaptic membrane Voltage-gated Ca2+ channel Postsynaptic membrane Ca2+ Synaptic cleft Ligand-gated ion channels Action potential

43. Na+ Neuro- transmitter K+ Postsynaptic membrane Ligand- gated ion channel Ca2+

45. Major Neurotransmitters

46. Muscle Contraction

47. Ca2+ Stopping the signal e.g., Cholinesterase (enzyme)

48. Playing with neurotransmitters

49. Precursor Neurotransmitters

50. Neurotransmitter Mimic