Robbins Ch. 28 Flashcards
Acute Neuronal Injury: -what causes this? -earliest marker of what process? -timing?
-caused by depletion of glucose, O2, or trauma -earliest morphological marker of neuronal cell death - Red neurons evident by 12-24 hours after insult
Morphology of red neurons
-shrinkage of the cell body -pyknosis of nucleus -disappearance of nucleus -loss of nissl substance -INTENSE EOSINOPHILIA
What would you see in a chronic neuronal injury?
-accumulation of abnormal protein aggregates
what is seen when neurons are cut?
axonal reaction: enlargement and rounding up of the cell body, increased protein syn, enlargement of the nuc, dispersion of Nissl substance from the center to the periphery (central chromatolysis)
Astrocytes: -what do they do? -contain what filament?
- they act as metabolic buffers and detoxify the brain; also contribute to the bbb -contain GFAP
Gliosis: -most important indicator of what? -characterized by what? -what changes are seen in astroyctes? -what is a name for these astrocytes
-most important indicator of CNS damage -characterized by hypertrophy and hyperplasia of astrocytes -astrocyte nucleus enlarges, becomes vesicular, and develops prominent nuclei -cytoplasm expands to a bright pink forming swaths around the eccentric nucleus that form numerous stout ramifying processes “gemistocytic astrocytes:
Rosenthal fibers: -characteristics -commonly seen w/ what tumors -contain which HSPs
-thick, elongated, brightly eosinophilic, irregular structures that occur within astrocytic processes -commonly seen w/ slow growing benign tumors -found in regions of long standing gliosis and characteristic of PILOCYTIC ASTROCYTOMA -contain ab-cystallin, HSP27 -also contain ubiquitin
Alexander dz -mutations in GFAP cause? -where do rosenthal fibers aggregate?
-leukodystrophy due to mutations in GFAP -contain lots of RFs in periventricular, perivascular, and subpial locations
Capora amylacea:
- also called ____ bodies
- shape/characteristics/staining?
- what causes them?
- AKA polyglucosan bodies
- round faintly basophilic, periodic acid schiff positive, concentrically lamellated
- increase w/ age and thought to be from ND dzs
- oligodendrocyte response to injury
- microglia response to injury
- oligodendrocytes–> injury or apoptosis of oligos is a feature of acquired demyelinating disorders and leukodystrophies
- Microglia–> respond by 1. proliferating 2. developing elongated nuclei 3. forming aggregates around small foci of tisssue necrosis (microglial nodules) 4. congregfating around cell bodies of dying neurons (neuronophagia)
- oligodendrocytes harbor viral inclusions in which dz?
- oligos have inclusions of a-synuclein in what dz?
- viral inclusions in PML
- a-synuclein inclusion in MSA
Cerebral edema:
-characteristics of gyri, ventricular cavities
gyri narrowed, ventricular cavities are compressed
- where are microglia derived from
- surface markers
mesoderm derived
CR3 CD68
- vasogenic edema:
- what fluid?
- whats happening to the bbb?
- brain lymphaticw
- often follows what type of insult
increased ECF in the brain from BBB disruption and increased vascular permeability
- problem is made worse by paucity of lymphatics in the brain
- vasogenic edema often follows an ischemic injury
cytotoxic edema:
- which fluid?
- injury from what
- increase in intracellular fluid secondary to neuronal, glial, or endothelial cell membrane injury
- might be encountered in someone w/ a generalized hypoxic/ischemic insult, or with a metabolic derangement that prevents maintenance of the normal membrane gradient
interstitial edema
- occurs where?
- when does this occur?
-occurs especially around the lateral ventricles when an increase in intracascular pressure causes an abmnormal flow of fluid from the intraventricular CSF across the ependymal lining to the periventricular white matter
Hydrocephalus
communicating vs non communicating
-communicating: the ventricular system is in communication w/ the subarachnodi space and t_here is enlargement of the entire ventricular system_
- non communicating: ventricular system is obstructed and does not communicate w/ the subarachnoid space–> may occur because of a mass in the third ventricle
Hydrocepalus ex vacuo:
-refers to a compensatory increase in ____
compensatory increase in ventricular volume seconeary to a loss of brain parenchyma
Herniation:
- subfalcine
- leads to compression of which a.
- asymmetric expansion of the cerbral hemisphere displaces the cingulate gyrus under the falx
- compression of the ACA
transtentorial (uncinate) herniation:
- which lobe is compressed against the tentorium?
- CN at risk?
- a. at risk?
- what is kernohan notch, and how does it happen?
- duret hemorrhages
- medial aspect of the temporal lobe is compressed against the tentorium
- cn III can become compromised–> pupillary dilation impairment of Ex Occ movement
- PCA–> ischemia of visual cortex
- contralateral cerebral peduncle can also become compressed resulting in hemiparesis ipsilateral to the side of herniation
- duret hemorrhages–> bleeds of midbrain/ pons
Tonsillar herniation:
- what is displaced
- why life threatening?
-cerebellar tonsils through the foramen magnum, life threatening because it compresses the brainstem and vital respiratory/cardiac centers