1. Neuronal Physiology Prepared by: Dr A. Riasi Isfahan University of Technology

2. Every cell in animal body displays a membrane potential.  Introduction

4. Neurons and muscles are excitable cells and can change their membrane potential.  Introduction

6. Terminology and methodology: Polarization Depolarization Repolarization Hyperpolarization  Introduction

7. How these information are prepared? There are two techniques for this kind of studies:  Introduction Using microelectrodes Patch clamping

8.  Introduction

9. A patch pipette on a cultured neuron

10.  Introduction The water-soluble ion have to penetrate the plasma membrane using the specific channels.

11.  Introduction Leak channels (non-gated channels) Gated channels Voltage-gated channels Chemically gated channels (ligand channels) Mechanically channels

12.  Two basic forms of electrical signals

17. We can describe the passive movement of electrical depolarizing by Ohm’s Law: ∆V m = ∆ I × R or ∆ I = ∆Vm × g  Two basic forms of electrical signals

18. Postsynaptic potentials Receptor potentials End-plate potentials Pacemaker potentials Slow-wave potential The graded potentials are critically important to neurnal function for example:  Two basic forms of electrical signals

34.  Propagation of an action potential Once initiated, action potentials are conducted over the surface of an axon by: Contiguous conduction Saltatory conduction

35.  Propagation of an action potential

39.  Absolute and relative refractory periods The refractory period ensures unidirectional propagation of the action potential and limits the frequency of action potentials.

40.  Absolute and relative refractory periods

41.  Action potentials occur in all-or- none fashion

42.  Myelination fiber

43.  Myelin as insulator layer

44.  Saltatory conduction

47.  Pre and post synaptic neuron

48.  Synapse structure

50. Excitatory Synapse from the Central Nervous System (TEM x27,360). This image is copyright Dennis Kunkel at www.DennisKunkel.com, used without permissionwww.DennisKunkel.com  Synapse structure

51.  Post synaptic potentials

52.  Grand post-synaptic potential

53.  Pre-synaptic inhibition

54.  Convergence and divergence