Path Block 6- CNS

  1. What are the unique features of the CNS?
    • selective vulnerability of neuronal systems: degeneration of specific nuclei and connections
    • mature neurons are post mitotic

    • anatomic/physiologic characteristics:
    • bone enclosure
    • metabolic substrate requirements 
    • no lymphatics
    • CSF
    • limited immune surveillance (physical barrier)
    • distinctive response to injury/healing: gliosis
  2. What do neurons look like?
    • large nuclei with prominent nucleolus
    • well definted cytoplasm w/ Nissl substance (RER)
    • shape varies depending on locatio in brain
    • neuromelanin: contains dopamine, seen in substantia nigra, degenerates in Parkinsons
  3. Image Upload 1
    lipofucin - accumulates with aging
  4. What are the 3 reactions of neurons to injury?
    • Eosinophilic changes (ischemia/hypoxia)
    • Central chromatolysis (axonal damage)
    • Intraneuronal inclusion formation
  5. Why does eosinophilic degeneration occur?  When does it manifest at the light microscope?  What is the morphologic criteria?
    • Lethal ischemia, hypoxia, or hypoglycemia
    • Takes 12024 hrs to manifest
    • Shrinkage of neuronal cell body
    • Loss of Nissl w/ cytoplasmic eosinophilia
    • Loss of nucleolus w/ nuclear pyknosis
  6. Image Upload 2
    • Red is dead
    • Eosinophilic degeneration
  7. What occurs in central chromatolysis?
    • manifestation of switch from manufacture of synaptic to structural proteins in response to axonal damage
    • reversible if axonal repair is successful
    • cellular swelling with margination of Nissl substance and nucleus and accumulation of filaments and organelles
  8. Image Upload 3
    • Central chromatolysis
    • ballooned cell- loses concavity - nissl gets pushed to edge of membrane
Card Set
Path Block 6- CNS
CNS Path