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neuron

lecture and practicals

mjcong
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neuron

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  1. Lab Activity 12 Histology of Nervous Tissue Martini Chapter 12 Institut Pendidikan Guru Malaysia PJM3106

  2. Neuron

  3. Myelin • Multilayered lipid and protein covering formed by Schwann cells around axons • Oligodendrocytes in the CNS • The covering is the plasma membrane of the Schwann Cell • The Schwann Cell can cover more than one axon • Insulates axon

  4. Nodes of Ranvier • Areas between Schwann Cells that do not contain Myelin • Involved in saltatory conduction

  5. Dendrite Neuron Cell Body Nucleus Axon Hillock Axon

  6. Schwann Cell Axon Node of Ranvier Myelin Sheath Telodendria Axon Terminal (Synaptic end bulbs)

  7. Unipolar Neuron • All are sensory afferent • Cell bodies are located in the dorsal root ganglia Dendrite (trigger zone) Axon Cell Body

  8. Bipolar Neuron • Location: special senses (smell, vision, hearing) Dendrite (trigger zone) Axon Cell Body

  9. Multipolar Neuron • Most common type of neuron • Interneurons and motor neurons Cell Body Axon Dendrites (trigger zone)

  10. Motor (Efferent) NeuronsEfferent = Away from CNS • These are neurons that carry information from CNS to the body • Groups of axons running together are the Nerves when they are outside the CNS and Tracts inside the brain and spinal cord • The cell bodies are clustered in groups in the CNS and are called nuclei • Brain gray matter is made up of millions of nuclei. • It is gray because there is no myelin around the cell bodies • These axons exit the spinal cord on the ventral side

  11. Sensory (Afferent) NeuronsAfferent = Toward the CNS • These carry sensory information from the body to the CNS (brain and spinal cord) • Their axons run in the same group as the motor neurons (nerves=groups of axons) • Their cell bodies are clustered outside of the spinal cord and are called ganglia • These axons enter the spinal cord on the dorsal side

  12. Association or Interneurons • Neurons between the afferent and efferent neurons. • Are only in the CNS

  13. Axon Myelin Sheath Neuron Node of Ranvier Perineurium Fascicle Epineurium

  14. Glial Cells • Associated with neurons • Provide Supportive scaffolding • Segregate and insulate neurons • Outnumber neurons by 10 to 1

  15. Star Shaped Many functions Control the chemical environment around neurons by buffering K+ and NT Exchanges between capillaries and neurons (blood-brain barrier) Nutrient transfer Supporting Cells in the CNS Astrocytes

  16. Supporting Cells in the CNS Oligodendrocytes • Oligodendrocytes produce the myelin sheath which provides the electrical insulation for some neurons in the CNS

  17. Supporting Cells in the CNSMicroglia • Small oval cells with long thorny processes • Monitor the health of neurons • Specialized immune cells that phagocytize microorganisms and debris • Immune system cells do not have access to CNS

  18. Supporting Cells in the PNS Schwann Cells • Form the myelin sheath around axons in the PNS

  19. Schwann Cell

  20. The End The End

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