Introduction to Neuropathology Flashcards
what gives rise to the three primary brain vesicles?
differential growth rates
what can the prosencephalon (one of three primary brain vesicles) be divided into?
telencephalon
diencephalon
what is the neural plate?
dorsal thickening of the cranial surface ectoderm
what three layers compose the neural tube?
ventricular zone
mantle zone
marginal zone
what happens in the spinal cord as the limb muscles mature?
increasing numbers of neurons populate the cervical and lumbar intumescences
what can the neural crest cells migrate away from midline to form?
sympathetic and parasympathetic ganglia
spinal (dorsal root) ganglia
melanocytes
enteric plexi
where do motor nerves originate?
ventral motor horn
what is the intermediate gray column?
sympathetic preganglionic neurons located between T1 and L4
where are most preganglionic neurons in the parasympathetic system located?
brainstem in various nuclei
sacral segments
how does the meninges support the brain and spinal cord?
protection
compartment for CSF
support for blood vessels
sheath for cranial and spinal nerves
what is central in the spinal cord and what is on the periphery?
gray matter central
white matter is peripheral
what are the layers of the meninges?
dura mater: outer
arachnoid
pia mater: inner layer
what surrounds penetrating blood vessels into the spinal cord?
pia mater
what is a common location for inflammatory disease?
meninges
what may happen with any inflammatory disease in the meninges?
proliferation of the arachnoid cells
where is a common place that cancer can develop in the CNS?
meninges
what are some cancers that can occur in the meninges?
meningioma
hematopoietic neoplasia: histiocytic sarcoma and lymphoma
what is dural ossification?
osseous metaplasia: normal bone with marrow
does not cause significant disease
what do neurons consist of?
dendritic zone
cell body
single axon
what do neurons transmit?
electrical and chemical impulses
what does it mean that neurons are post-mitotic?
cannot be replaced after loss
what are some immunohistochemical stains that can be used on the CNS?
synaptophysin
neuN
PGP9.5
MAP2
S-100
what does neuronal necrosis vs apoptosis depend on?
underlying disease process
what is neuonophagia?
degenerate/dying neuron is ingested by macrophages
what happens in laminar cortical necrosis?
segmental layers of the cerebral cortex are wiped out
what can cause laminar cortical necrosis?
thiamine deficiency (ruminants, camelids, small animals)
sulfur toxicity (ruminants)
hypoxic/ischemic damage
lead toxicity (ruminants)
salt toxicity (swine)
what can cause neuronal chromatolysis?
toxin exposure
metabolic disease
genetic diseases
why do axons react to many forms of injury by swelling?
anterograde/retrograde transit of axoplasmic organelles
what can cause spheroids?
compressive damage
inherited/genetic diseases like neuroaxonal dystrophy
lysosomal storage diseases
aging
what is wallerian degeneration?
fragmentation and dissolution of the distal part of the axon and digestion/removal of the collapsed myelin tube
what are the two populations of astrocytes?
large protoplasmic forms
fibrous forms
what is an astrocytoma?
type of glioma that has astrocytic features
tumor cells can have variable appearance similar to reactive astrocytes
what is CNS myelin formed from?
modified processes of oligodendrocytes
what can cause satellitosis?
infection, especially viral and protozoal
inborn errors of metabolism in neurons
toxin exposure
hypoxic/ischemic damage
what do ependymal cells do?
line ventricular system
role in movements of CSF via undulations of surface cilia
what is the choroid plexus?
specialized ependymal cells
with epithelial cells, forms blood-brain barrier
produces CSF
what can ependymitis result in?
hydrocephalus due to obstruction of CSF flow
where is the choroid plexus located?
lateral, third, and fourth ventricles
what are microglia derived from?
yolk sac: extraneural lineage
mesodermal origin
when can gitter cells be seen?
areas of necrosis
what are glial nodules?
foci of gliosis and scattered inflammatory cells
in areas of necrosis, capillary blood vessels respond by _______________________________
endothelial swelling and hyperplasia (capillary sprouting)
what is vasogenic edema from?
vascular injury that breaks down blood-brain barrier and allows fluid to leak
thrombosis, inflammation, infarcts
what are the three anatomic quadrants that peripheral nerves are divided into?
epineurium
perineurium
endoneurium
what is spina bifida?
absence of thee dorsal arch of spinal vertebrae
where is spina bifida most common?
lumbosacral region
who is anury and brachyury most common in?
manx cats
english bulldog
what is diplomyelia?
spinal cord duplication within a single leptomeninges
what is myeelodysplasia?
general term for alteration in normal anatomic arrangement of the spinal cord
what is equine myelodysplasia?
invasion of peripheral schwann cells into the CNS, causing mass-like lesions
what is arnold-chiari-like type II malformation?
caudal fossa is reduced in size (and volume)
associated with elongation of the cerebella vermis and medulla
what is hydrocephalus?
increase in volume of the CSF
what are encephaloclastic defects due to?
acquired destructive processes
what is hydranencephaly due to in veterinary medicine?
almost always viral infection in utero
what is cerebellar hypoplasia/aplasia most commonly due to?
in utero infection with pestivirus, parvovirus, or orthobunyavirus
what is lissencephaly?
brain that lacks normal gyri and sulci
what type of dog is lissencephaly most common in?
Lhasa apso dog: genetic in origin
what is polymicrogyria?
excessive number of sulci and gyri, most commonly in caudal cortex
what are some cancers that can develop in the meninges?
meningioma
hematopoietic neoplasia: histiocytic sarcoma and lymphoma
what is chromatolysis?
neuronal degeneration (a type): neuron swells, nucleus marginalized, dispersal/loss of nissl substance
do non-viral neural inclusion bodies usually cause damage?
not to the neuron
what is the initial axonal breakdown in wallerian degeneration dependent on?
recruitment of macrophages: digestion chambers
what is glia limitans?
a layer of astrocyte foot processes subjacent to pia mater that provides surface protection
what do astrocytes do?
control microenvironment with homeostasis
express MHC I and II
repair
provide guidance/support for neuronal migration during development
influence induction tight junctions
form glia limitans
what do you need to assess astrocyte injury?
GFAP
what are type II alzheimer cells?
pattern of astrocytes clumped with open chromatin
caused by high ammonia
what are the three phenotypic forms of microglia?
resting
ameboid
reactive/rod-shaped
what is Iba1 immunohistochemistry specific to?
macrophage lineage cells
where is spina bifida most common?
lumbosacral region
what is myeloschesis?
cleft formed by inappropriate neural tube closure
in dogs, who is most commonly affected by arnold-chiari-like type II malformation?
cavalier king charles spaniel
what are encephaloclastic defects due to?
acquired destructive process
what do reactive astrocytes look like?
broad, polygonal
nucleus at margin
others elongate
what is astrogliosis?
increased synthesis of intermediate filaments and increased branching and complexity of processes
how are microglia distributed?
evenly in grey and white matter
what is hydrancephaly?
almost complete destruction and lack of development of neocortex
what is cerebellar hypoplasia/aplasia due to?
usually pestivirus, parvovirus, or orthobunyavirus in utero
in whom is polymicrogyria most common?
standard poodles
