Learning Objectives

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Learning Objectives

• Describe the two major divisions of the nervous
  system and their characteristics
• Identify structures/functions of a typical
  neuron.
• Describe the location and function of neuroglia.
• Describe myelination in PNS.

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Nervous System
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Neuronal Structures

•         soma (cell body)        dendrites   
      axons        axon hillock/trigger zone
  axon terminals                               
               

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Anatomy of a Multipolar Neuron
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Structural Classification of Neurons
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Structure of a Typical Synpase
Figure 12.3
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Neuroglia of the CNS

• Four types of neuroglia in the CNS
• Ependymal cells
• Related to cerebrospinal fluid
• Astrocytes
• Largest and most numerous
• Oligodendrocytes
• Myelination of CNS axons
• Microglia
• Phagocytic cells

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Figure 12.6 An Introduction to Neuroglia
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Neuroglia of the PNS

• Two types of neuroglia in the PNS
• Satellite cells
• Surround neuron cell bodies within ganglia
• Schwann cells
• Ensheath axons in the PNS

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Myelinated axon
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Ranvier, Louis-Antoine 1835-1922
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Definitions

• Neuron nerve cell
• Nerve fiber any long process of a neuron.
  The term usually refers to axons, but can
  include dendrites
• Nerve A collection of nerve fibers in the
  peripheral nervous system.

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Structure of the Peripheral Nerve
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