Pathology of the CNS

• The brain has no lymphatic drainage, and when it scars its scars are glial, not fibrotic

• Changes in neurons

  • Chromatolysis is a characteristic response in neurons after axonal injury; cell body swells up a bit and the nissl bodies disappear

  • Red neurons are dead (from ischemia)

  • Atrophy/degeneration – slow loss with glial reaction

  • Intranuclear/intracytoplasmic inclusions (especially after viral infections)

• Changes in glial cells

  • Astrocytes

    • Gliosis: increase in astrocytes (size and number) in response to different injuries; very nonspecific

    • Alzheimer type II change: seen in hepatic encephalopathy

  • Oligodendrocytes: demyelination

  • Ependymal cells: ependymal granulations (from inflammation)

  • Microglia

    • Rod cells

    • Nodules (especially in response to viral infection)

    • Phagocytosis

Category: Medical Subject Notes , Pathology Notes