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IB. Neurons - pathological changes

Neurons - Pathological reactions (cont)

d. Subcellular alterations in cytoplasm, organelles or cytoskeleton:  A wide range of subcellular alterations are recognized.

  • Neuronal inclusions may occur as a manifestation of aging. This can involve cytoplasmic accumulation of lipids, proteins and carbohydrates (lipofuscin)
  • In many cases of viral encephalitis, inclusion bodies composed of viral particles occur in the cytoplasm or nucleus of infected cells. One example is the Negri body characteristic of rabies.
  • In some degenerative diseases, specific types of intraneuronal inclusions characteristically occur. For example, in Parkinson's disease, large spherical intracytoplasmic inclusions called Lewy bodies are found. In Alzheimer's disease, cytoplasmic accumulation of abnormal neurofilaments, called neurofibrillary tangles occurs.
  • Neurons may be the site of storage of uncatabolized substances, such as lipids, in a number of inborn errors of metabolism resulting from deficiencies of lysosomal enzymes.

 

Example of neurofibrillary tangles in a silver-stained section of cerebral cortex.  The cytoplasm of the cell at the bottom is black -filled with paired helical filaments.  One cell in the center of the field is normal.
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