Intro to Neuropathology Flashcards
percentage of genes coding for nervous system-related proteins
50%
selective vulnerability of the hippocampus
hypoxic/ischemic changes
selective vulnerability of the caudate nucleus
Huntington’s disease
selective vulnerability of the motor neurons
amyotrophic lateral sclerosis (ALS)
selective vulnerability of substantia nigra
Parkinson’s disease
type of neurons most resistant to injury
astrocytes
selective vulnerability of oligodendria
myelin disorders
3 types of glial cells
astrocytes, oligodendocytes, ependymal cells (NOT microglia)
if needed, microglia can transform into ..
histiocytes
Nissl substances are representative of
rough endoplasmic reticulum
what part of the neuron stains with H&E?
nucleic acids
major mechanisms of cellular injury
free radical injury, excitotoxic injury
examples of excitotoxic injury
glutamate, aspartate; depolarization; NMDA amino acid receptor
*what is the mechanism of excitotoxic injury?
injured neurons release their excitatory NTs (glutamate), which results in depolarization of the surrounding neurons through the inappropriate activation of NMDA receptors
how can you protect against excitotoxic injury?
antioxidants
excitotoxic injury via NMDA receptors results in..
calcium influx that interferes with mitochondrial function which eventually leads to cell death
characteristics of acute neuronal injury
eosinophilic necrosis (red), hypoxic injury, shrunken cytoplasm, dark smudgy chromatin, irreversible cell death
how long does it take for acute neuronal injury to show up on light microscopy?
12 hrs
hippocampus CA1 region (Sommer’s sector) is most sensitive to what type of injury?
hypoxic-ischemic
subacute and/or chronic type of neuronal injury
degeneration
the changes that occur in the neuron body in response to axonal injury is termed..
axonal reaction (formerly known as central chromatolysis); regenerative attempt
examples of axonal reaction
damage to axon, margination of Nissl substance, central clearing of the cytoplasm, peripheral displacement of the nucleus, rounding of the cell body
term for when an axon is transected, and the proximal portion starts to regenerate and myelinate
Wallerian degeneration
if the BM is not intact during Wallerian regeneration, what is the outcome?
chaotic proliferation of axons, resulting in a painful nodule called traumatic or amputation neuroma
how are neuromas treated?
can be anastomosed to facilitate healing, or if damage is extensive, nerve transplantation can be done
what are axonal spheroids and how do they form?
when an axon is transected, the transport material going towards the synapse will accumulate at the site of injury
identification of axonal spheroids on path slides is important because..
it helps confirm presence of an infarct next to them; also in the diagnosis of such things as diffuse axonal injury
stain used to highlight axonal spheroids/swelling
silver stains
most common neuronal inclusion
viral inclusion
a neuronal inclusion seen with Parkinson’s disease pathology
Lewy body
inclusion seen in Pick’s disease/frontotemporal lobar degeneration
Pick’s body
inclusion seen in alzheimer’s
neurofibrillary tangles (accumulate in the cytoplasm)
what is trans-synaptic degeneration?
secondary degeneration of a neuron connected to a dying neuron; can be counter-intuitive; anterograde or retrograde
what physically happens to astrocytes when they react?
develop plump cytoplasm, processes become more prominent; indicates some pathology
inclusions representative of a hyperammonemia typically seen with cirrhosis
Alz type II glia (astrocytes)- nothing to do with Alz
astrocyte pathology typically seen with demyelinating diseases like MS
Creuzfeldt astrocyte
neuronal inclusion made of GFAP and B-crystalline
Rosenthal fibers (slow-progressing, in the cytoplasm)
fried egg appearance
oligodendrocytes
oligodendrocyte inclusions are seen in this disease
progressive multifocal leukoencephalopathy
the diagnostic value of oligodendrogial changes
satellitosis around neurons and blood vessels by the neoplastic cells infiltrating grey matter areas.
two major changes associated with reactive microglia & what they’re associated with
microglial nodules, neuronophagia; most commonly associated with viral infections of the CN
PNS biopsies are usually taken from the..
sural nerve (entirely sensory)
pathologic characteristic of Charcot-Marie-Tooth disease
“onion bulb” Schwann cell in the PNS resulting from constant remyelination and demyelination
technique using chemical reactions to highlight certain tissue components like mucin, myelin, collagen
histochemistry
special staining technique for astrocytes using antibodies raised against specific components of cells
immunohistochemistry
in-situ hybridization is used to show the presence of
DNA segments
