Nervous System I

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Nervous System I

• April 19, 2007
• BIOL 203
• Karen Kraus

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The nerve of some people!

• Master control and communication system
• three overlapping functions
• gathering sensory input
• processing stimuli (integration)
• responding to sensory input (motor output)

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Organization

• Nervous system
• peripheral vs. central
• motor vs. sensory (efferent vs. afferent)
• autonomic vs. somatic
• sympathetic vs. parasympathetic

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Supporting Services

• Nervous tissue neurons and neuroglia
• six types of glial cells
• astrocytes
• microglia
• ependymal
• oligodendrocytes
• Schwann cells
• Satellite cells

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The stars above...

• Astrocytes
• most numerous
• support and scaffold
• exchanges between blood and neurons
• guiding neuronal migration
• taking up excess potassium

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Wrapping garments

• Ependymal cells
• often ciliated
• line ventricles and CSF cavities
• help to make and circulate CSF

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Pruned

• Oligodendrocytes
• CNS myelination

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Little guys

• Microglial cells
• nurses of the CNS
• phagocytic cells

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Mooning

• Satellite cells
• unknown function

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Ugly duckling

• Schwann cells
• neurolemmocytes
• PNS myelination
• axonal regeneration

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Das Neuron!

• Ability to conduct nerve impulses
• extreme longevity
• amitotic (generally)
• high metabolic rate, with requisite high oxygen
  and glucose needs

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Structure of a Neuron

• Cell body
• perikaryon
• soma
• Dendrites
• receptive region
• Axon
• conducting region

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More structure
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Husk of what it once was...

• Neurilemma vs. myelin sheath

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A difference of opinion

• Nucleus
• a group of CNS cell bodies
• also called basal nucleus or basal ganglion
• Ganglion
• a group of PNS cell bodies

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More differences

• Tract
• a group of CNS axons/dendrites (nerve fibers)
• Nerve
• a group of PNS axons/dendrites (nerve fibers)

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A little class act

• Structural vs. functional
• structure
• number of extensions
• unipolar, bipolar, multipolar
• function
• direction of impulses
• afferent, efferent, inter

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Need some structure...

• Structure of a typical nerve
• epineurium
• perineurium
• endoneurium
• fascicle
• spinal vs. cranial