Midterm paper
paez1991
download-15.pdf
3. Nervous System Cells
A. Neurons B. Neuroglia
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A. Structure of Typical Neuron
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Structural Classification of Neurons
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Two Examples of CNS Neurons
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Pyramidal cell of cerebral cortex
Purkinje cell of cerebellar cortex
B. Neuroglias
a) Central Nervous System • Astrocytes • Oligodendrocytes • Ependymal cells • Microglias
b) Peripheral Nervous System • Schwann cells • Satellite cells
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a) Neuroglia of CNS
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Astrocytes • Largest and most numerous • Star-shaped cells • Astrocyte processes make contact with:
• Blood capillaries • Neurons • Pia mater
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Functions of Astrocytes
• Provide strength • Maintains unique permeability characteristics of
endothelial cells • In embryo: secrete chemicals that appear to regulate:
• growth, migration, and interconnections
• Maintains appropriate chemical environment for generation of nerve impulses
• Play a role in learning and memory by influencing formation of neural synapses
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Oligodendrocytes • Processes - responsible for forming myelin sheath
• insulates axon and increases speed of nerve impulse conduction
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Microglial Cells or Microglia
• Small cells with slender processes • Originate from red bone marrow
• function as phagocytes
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Ependymal Cells • Cuboidal to columnar cells • Line ventricles of brain and central canal of spinal cord • Functionally:
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• produce, possibly monitor, and assist in circulation of cerebrospinal fluid
• Form blood–cerebrospinal fluid barrier
b) Neuroglia of PNS
a) Schwann cells b) Satellite cells
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Myelinated and Unmyelinated Axons
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