B7.012 Prework 1: Essentials of Neuropathology Flashcards
neuro cell types
neurons glia -astrocytes -oligodendrocytes -ependymal cells -microglia meningothelial cells
2 unique principles of neurons
- selective vulnerability
- post mitotic cells
- no regeneration
what causes the formation of red neurons
acute neuronal injury
-anoxia, ischemia, hypoglycemia
how are red neurons made
cell atrophy
nuclear pyknosis
loss of Nissl and nucleolus
appearance of red neurons on H&E
loss of H leaving E
eosinophilia = red
reaction of neurons to injury
- atrophy
- retraction of cell body, nuclear pkynosis (smaller, darker) - degeneration
- apoptosis - axonal reaction
- injury to axon leads to cell body swelling
- central chromatolysis (due to Nissl displacement) - Wallerian degeneration
- degeneration of nerve fibers distal to injury - trans-synaptic degeneration
- atrophy of nerve cells due to loss of afferent input
pigments in neurons
lipofuscin
neuromelanin
lipofuscin
pigment of old age
neuromelanin
pigment produces in substantia nigra
types of neuronal inclusions
granulovacuolar degeneration
neurofibrillary tangles
Lewy bodies
viral inclusions
what is granulovacuolar change and when is it seen
granules present in cytoplasm
seen in normal aging and AD
what are neurofibrillary tangles and when are they seen
dense protein fibrils
stain w silver and H&E
seen in AD
what are bunina bodies nd when are they seen
inclusions in large neurons of the spinal cord
seen in motor neuron disease
what are lewy bodies and when are they seen
eosinophilic, round intracytoplasmic inclusions with a halo
stain positive for a-synuclein
seen in substantia nigra
hallmark of Lewy body dementia
example of a viral inclusion
Negri body
seen in rabies
what are glial cells
supportive cells
make up most of brain parenchyma
function in inflammation, repair, and fluid balance
neuroectoderm derivatives of glial cells
astrocytes
oligodendrocytes
ependymal cells
mesoderm derivatives of glial cells
microglia (macrophages of CNS)
astrocytes
small oval nuclei with star like processes
supportive stroma of CNS
metabolic support, detoxifiers
foot processes help as a barrier (BBB)
contain glial fibrillary acidic protein (GFAP)
what is GFAP
glial fibrillary acidic protein
intermediate filament of the CNS
pathologies of astrocytes
gliosis (astrocytosis)
-indicator of injury, wall off an infarct
Rosenthal fibers
-mark stagnant astrocytes
Gemistocytic astrocytes
large, globular cell bodies filled with eosinophilic cytoplasm
seen in reactive or neoplastic processes
Alzheimer type 2 astrocytes
pseudoinclusions
seen in metabolic encephalopathy (hepatic failure)
-likely due to increased ammonia
Rosenthal fibers
astrocytic process inclusions
composed of HSPs, ab-crystallin
pink, fibrillary, dense material
what are Rosenthal fibers seen in
chronic gliosis
pilocytic astrocytomas
Alexander’s disease
corpora amylacea
5-50 um structures associated with astrocytic foot processes
contain HSP, ubiquitin
called “brain sand”, basophilic degraded proteins that form inclusions
causes of corpora amylacea
degenerative change
increase with age
function of oligodendrocytes
make and maintain myelin
stain blue
tumors of oligodendrocytes
oligodendrogliomas
injuries of oligodendrocytes
myelin loss or abnormal myelin
when are inclusions seen in oligodendrocytes
infections -JC virus neurodegeneration -demyelination -progressive multifocal leukoencephalopathy
describe oligodendrocytes nuclear inclusions
smudgy, viral like inclusion
ependymal cells
ciliated columnar cells
line the ventricular system
injury to ependymal cells
loss
infectious
-CMV
tumors of ependymal cells
ependymomas
-trying to make a ventricle unsuccessfully
choroid plexus
CSF producing cells
tumors of choroid plexus
papillomas
carcinomas
microglial cells
resident CNS macrophages actions: -proliferation -elongation -microglial nodules -neuronophagia
what is neuronophagia by microglial cells
cluster around dying neurons
composition of arachnoidal / meningothelial cells
keratin
“skin” cells of CNS
whorls are seen here
