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

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Presentation on theme: "Neuronal Physiology Prepared by: Dr A. Riasi Isfahan University of Technology."— Presentation transcript:

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

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

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

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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

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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

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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

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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

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47  Pre and post synaptic neuron

48  Synapse structure

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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


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