histologic structure of nervous system

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histologic nervous system, neuron, neuroglial, axon, dendrite, brain, spinal cord, blood-brain barrier

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  • 1. HISTOLOGY OF NERVOUS SYSTEM DR. I WAYAN SUGIRITAMA,M.Kes HISTOLOGY DEPARTMENT MEDICAL FACULTY OF UDAYANA UNIVERSITY

2. NERVOUS SYSTEM

  • The most complex system in the human body
  • Formed by network more than 100 million neuron
  • Each neuron has a thousandinterconnection a very complex system for communication
  • Nerve tissue is distribute throughout the body, anatomically divide into :CNS&PNS
  • Structurally consist :nerve cells&glial cells

23/06/09 3. CONTENTS

  • Cells of nervous system
  • Synaptic communication
  • Central nervous system & Peripheral nervous system & associated structure
  • Regeneration of nervous system

23/06/09 4. REFFERENCES

  • Color Textbook Histology, third edition, leslie P. Gartner
  • Basic Histology, tenth edition, L. Carlos Junqueira,2003
  • Histology and Cell Biology, second edition,2007
  • Elseviers Integrated Histology,2007

23/06/09 5. CELLS OF NERVOUS SYSTEM 23/06/09 NEURON NEUROGLIA 6. STRUCTURE OFNEUR ON

  • Principle cells of Nervous Tissue
  • Consist of3parts:
    • CELL BODY(perikaryon/soma)
    • A singleAXON
    • MultipleDENDRITES
  • 5-150m

23/06/09 7. CELL BODY (PERIKARYON)

  • Central portion of the cell
  • Generally are polygonal
  • Different shape and sizecharacteristic regions of nervous system
  • Contain :
    • Nucleus
    • Perinuclear cytoplasm

23/06/09 8. ULTRASTRUCTURE OF NEURON

  • Nucle us:
  • large,spherical to ovoid and centraly located
  • a single prominent nucleolus
  • finely dispersed chromatin
  • trancriptionaly active

23/06/09 9. ULTRASTRUCTURE OF NEURON

  • Cytoplasm :
  • A bundantofR.E.R
  • Polyribosomes
  • Basic dyes (a+b) Nissl Bodies
  • lots ofS.E.R.
  • Golgi bodies(perikaryon)
  • protein secreting cell

23/06/09 10. ULTRASTRUCTURE OF NEURON

  • Cytoplasm
  • M any mitochondria,most abundant in axon terminal
  • extensive cytoskeleton axonal transport
  • One centriole do not undergo cell divisions

23/06/09 11. DENDRITE AND AXON

  • AXON
    • Single processu p to 100 cm
    • Originate fromaxon hillock
    • Devoid ribosome
    • Dilatation ofdistal portion axon terminalend bulbs synapse
    • conducting impulseaway from the soma
    • Axonal transport
  • DENDRITES
    • Multiple elongated processes
    • Cytoplasmic~perikaryon (devoid golgi complex)
    • Receiving stimuli

23/06/09 12. NEURONS CLASSIFICATION :

  • According to the size and shape of the processes

(Dorsal root & cranial nerve ganglia)(Pyramidal & purkinje) 23/06/09 13. NEURONS CLASSIFICATION : 23/06/09 14. NEURONS CLASSIFICATION :

  • According to their function :
  • Sensory Neuron (afferent )
    • Receive sensory inputconduct impulses to CNS
  • Motor Neuron (Efferent)
    • CNSconduct impulses to muscles, glands and other neurons
  • Interneuron
    • In the CNS as interconnectors, establish neuronal circuit between sensory and motor neuron

23/06/09 15. NEURON GROUPING

  • CORTEX
    • Neuron form six layers on the cerrebrum
    • Form three layers on the cerrebellum
  • NUCLEI
    • In subcortical region (thalamus, midbrain, brainstem and spinal cord) neuron form irregular clusternuclei
  • GANGLION
    • Cluster of neuron outside the CNS

23/06/09 16. FUNCTION OF NEURON

  • R eceptive
    • Receptor receive stimuli and tranduce into nerve impulse and transferro to other neuron
  • I ntegrative
    • Processing impulse on the higher center
  • M otor
    • Initiating motor respons and tranduse impulse to the effector

23/06/09 17. SYNAPS ES

  • Sites of impulse transmission
  • Convert electrical signal into chemical signal
  • Permit neurons to communicate
  • Types of synapses :
    • Axodentritic synapse
    • Axosomatic synapse
    • Axoaxonic synapse
    • Dendrodentritic synapse

23/06/09 18. SYNAPS 23/06/09 19. NEURO GLIAL CELLS

  • Metabolicandmechanicalsupport forneuron
  • 10 times abundant than neurons
  • Neuroglial cells undergo mitosis
  • Classification :
    • Oligodendrocytes
    • Astrocytes
    • Ependymal Cells
    • Microglia
    • Schwan cells

CNS PNS 23/06/09 20. NEURO GLIAL CELLS

  • Astrocytes
    • Pedicles bindsto capillaries and to the pia materformglial limitans
    • Controlling the ionic&chemical env ironmentof neurons
    • Energy metabolism
    • Form cellular scar tissue
    • Form the blood-brain barrier

23/06/09 21. NEURO GLIAL CELLS

  • Oligodendrocytes
  • interfascicular
    • Produce myelin sheath (electrical insulation) in CNS
    • A single cell wrap several axons (40 to 50)
    • Form nodes of Ranvier
  • satellite

23/06/09 22. NEURO GLIAL CELLS

  • Schwann cells
    • Analogueto Oligodendrocyte
    • Produce myelin sheath in the PN S

23/06/09 23. NEURO GLIAL CELLS

  • Microglia
  • Scattered throughout the CNS
  • Clearing debris
  • Act as APC
  • Protect the CNS from viruses and microorganism

23/06/09 24. NEURO GLIAL CELLS

  • Ependymal Cells
    • Low columnar ciliated epithelial cellsline theventricles of the brain & central canal spinal cord
    • Formation ofchoroid flexusproduce CSF
    • Facilitates the movement of CSF

23/06/09 25. Anatomically divided in to : 06/23/09 NERVOUS SYSTEM CENTRAL NERVOUSSYSTEM (CNS) PERIPHERAL NERVOUSSYSTEM (PNS) 26. THE CNS

  • Consist of :
    • Cerebrum
    • Cerebellum
    • Spinal cord
  • No connective tissue soft, gel like
  • When sectioned :
    • White matter
    • Gray matter
  • Covered by meninges

06/23/09 27. CEREBRUM

  • GRAY MATTER
    • Contains neuronal cell bodies, dendrites and glial cells
    • Six layers composedof neuron
    • Neuron(pyramidal) :
      • Afferent (sensory)
      • Efferent (motor)
  • WHITE MATTER
    • Contains myelinated axons and myelin-producing oligodendrocytes

23/06/09 28. CEREBELLUM

  • GRAY MATTER
    • Three layers :
      • Outer molecular layer
      • Central layer of largePurkinje cells
      • Inner granule layer
  • WHITE MATTER
      • The same as cerebrum

23/06/09 29. SPINAL CORD

  • GRAY MATTER (CENTRAL) SHAPE OF H
    • Central canal lined byEpendymalcells
    • Legs of the H form :
      • Anterior horns
      • Posterior horns
    • Neurons : large and multipolar
  • WHITE MATTER (PERIPHERAL)

23/06/09 30. PN

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