Nervous System- Sys Path 2 Flashcards
the main neural progenitors are located in the
___________ _________ during development; reduced to
less than 1% at birth
neural tube
true/false: neuronal numbers are highly regulated
during development by stem cell proliferation and
controlled apoptosis
True
stem cells remain near the ____________ and replace
hippocampus and olfactory neurons of adult
mammals, but these numbers diminish with age
Ventricles
transport type of axons where materials travel away
from the cell body at about 400mm/day
fast orthograde transport
transport type of axons where materials travel
towards the cell body at 100-400mm/day
Retrograde transport
transport type of axons where materials travel away
from the cell body at 4mm/day
slow orthograde transport
oligodendrocytes produce myelin in the
(CNS/PNS )
CNS
schwann cells produce myelin in the (CNS/PNS )
PNS
regulate the microenvironment around synapses;
makes glutamine and participates in GABA uptake job within the CNS is to detoxify, aid/hinder axon
growth, form scar-like support after an injury, and
form networks to support neurons
Astrocytes
include the dura mater and subarachnoid
Pachymenix
includes the arachnoid and pia mater
Leptomeninges
The ______ ______ has tight junctions and fenestrated capillaries, CSF turned over 4-12x daily
choroid plexus
_____ _______ can contribute up to 59% of exiting CSF in dogs
interstitial fluid
_______ reduces the effective brain weight of humans and mammals
CSF
Simple ciliated epithelium with gap junctions that line the brain ventricles
ependyma
made up of non-fenestrated endothelium and astrocytic foot processes with an aquaporin channel
blood brain barrier
the lymphatic system equivalent in the CNS, most effective during sleep
glymphatic system
CSF moves along the peri-
arterial spaces > through the
brain parenchyma > exits as
interstitial fluid (ISF) along the
peri-venous space to the
cervical lymph system
glymphatic flow
extensions of the arachnoid mater that allow excess CSF to be absorbed
arachnoid granulations
the ______ are populated by lymphocytes and APCs that respond to local inflammation
meninges
T/F: All animals have arachnoid granulations
false
________ provide a niche for development of immature B cells that migrate from the skull basement membrane through micro channels
meninges
cells in the ___-___ ___ often end up in the CSF
Virchow-robin space
the lymphatic vasculature along the _____ sinuses connects the brain’s lymph to cervical LN
sagittal
CSF that is absorbed through the arachnoid granulations is channeled into _____ _____
dural veins
cells that have roles in synaptic pruning and axonal guidance, phagocytosis of apoptotic debris, and reduction of proinflammatory cytokines
microglial cells
The processes of these cells are actively surveilling the interstitial microenvironment
microglia
Neurons are ____-_____ cells with specific, often irreplaceable functions
post-mitotic
mean arterial pressure- intracranial pressure =
cranial perfusion pressure
T/F: the soft epithelial nature of the CNS makes it susceptible to injury
true
injuries that alter the glymphatic flow will often result in brain _____ or accumulation of toxic products
edema
the most severe lesions of therein originate from a defective ____ ____; abnormal closure of early destruction of tissue
neural tube
neural tube failure/necrosis; born without all or part of your brain
anencephaly
defective cranium formation
exencephaly
meninges + brain tissue herniated into a sac outside the cranium
meningoencephalocele
herniation of the meninges outside the cranium
meningocele
cranial bone closure deformations are often ______ in location in dogs (meningocele)
nasal
failure of one or more vertebral arches to close during fetal development
spina bifida
hernia of the spinal cord and meninges
myelomeningiocele
hernia in which the meninges protrude through an opening in the spinal cord
meningocele
most common and least severe form of spinal bifida without protrusion of the spinal cord or meninges
spina bifida occulta
neurons and oligodendroglia most often undergo ______ in response to in injuries
necrosis
astroglia and microglia undergo _____ in réponse response to injuries
hypertrophy
degeneration of a nerve distal to a physical or functional injury; axon and myeline degenerate together
wallerian degeneration
cytoskeletal degeneration, dephospho rylation of neurofilaments, and ischemia results in a _______ _______ in wallerian degeneration
transport blockade
Yes/No: is demyelination possible with wallerian degeneration?
yes
if regeneration is unsuccessful following wallerian degeneration, _______ _______ of the distal nerve and muscle occurs
permanent atrophy
the (CNS/PNS) is more likely to regenerate following injury
PNS
axonal regeneration depends on how well the proximal and distal ends of the damaged nerves are ________
aligned
T/F: an injury too close to the cell body of a neuron will likely not regenerate
true
Type of wallerian degeneration where trauma driving a thoracic limb caudally pulls the spinal nerves from the spinal cord
brach plexus avulsion
occurs mostly in older dogs around the cervical region; outer annulus fibrosis from vertebral disk protrudes chronically into the spinal cord
intervertebral disc disease type II
occurs with chondrodystrophic dogs around throacoumbar junction; nucleus pulpous extrudes through the annulus fibrosis to compress the spinal cord
intervertebral disc disease type I
most wallerian degeneration affects primarily _____ ______ within the spinal cord via the ischemia mechanism
ventral funiculi
T/F: spinal cord compression has to be very severe to affect the grey matter
true
With wallerian degeneration of the spinal cord, typically (ventral/dorsal) white tracts will degenerate the most severely when caudal to the site of the injury
ventral
With wallerian degeneration of the spinal cord, typically (ventral/dorsal) white tracts will degenerate the most severely when cranial to the site of the injury
dorsal
Lesions of the spinal cord caused by ischemia… occurs caudal and cranial to the site of injury
watershed lesions
vertebral instabilities in dogs and ______ is another cause of wallerian degeneration
horses
damage to fast orthograde transport will cause:
A. wallerian degeneration
B. proximal axonopathy
C. distal axonopathy
A.
damage to slow orthograde transport will cause:
A. wallerian degeneration
B. proximal axonopathy
C. distal axonopathy
B.
damage to retrograde transport will cause:
A. wallerian degeneration
B. proximal axonopathy
C. distal axonopathy
C.
progressive neurologic disorder of horses characterized by diffuse degeneration of axons, myelin, and neurons in the spinal cord and to lesser degrees of the brain stem
equine degenerative myeloencephalopathy
disorder in horses that is characterized by abnormal inspiratory noise during exercise associated with degeneration of the left recurrent laryngeal nerve and atrophy of the laryngeal muscles
equine laryngeal hemiplegia
______ _____ can be left by DNA and RNA viruses in the nucleus and cytoplasm respectively in some neuropathies
viral incluions
accumulation of insoluble products of proteosomal degradation within neurons results in ____ ______
cell death
what color = dead when it comes to microscopic lethal injury to neurons?
red
process that occurs when there is an acute, lethal injury to a neuron
necrosis
neuronal necrosis in the brain results in neuronal loss microscopically, but grossly, the result is brain ______
atrophy
excitatory neurons will die after an ischemic event due to increased ______ release with astrocytes being unable to detoxify the neurotransmitter and ion pumps releasing calcium into the cytoplasm (after dendrites take up excess of this)
glutamate
premature degeneration of purkinje cell layer of cerebellar cortex
cerebellar abiotrophy
degeneration of myelin without axonal degeneration; longest fibers most severely affected
demyelination
demyelination gross lesions are shown as _______ of the white matter
discoloration
some causes of ______ are oligodendrocyte death, autoimmune disease, and chemical damage to the myeline sheath
demyelination
inflammatory demyelination of ventral roots of PNS and CNS nerves; cause is thought to be a campylobacter infection
coonhound paralysis
abnormal increase in the number of astrocytes due to the destruction of nearby neurons
astrogliosis
an _____ _____ is partly derived from stem cells and from division of mature astrocytes
astroglial scar
presence of microglia in nervous tissue secondary to injury
microgliosis
________ develop activated phenotypes and, with cell damage, become macrophages after being stimulated by cytokines
microglia
referes to microglial cells that become phagocytic/active because of increased CNS damage
gitter cells
defective formation of the spinal cord; tissue is disorganized
myelodysplasia
congenital absence of the cerebral hemispheres caused by occlusion of the carotid arteries (ischemia); fluid replaces cerebral tissue
hydraencephaly
cavity in the brain, usually the result of a destructive lesion
porencephaly
condition characterized by abnormal openings or clefts in the cerebral hemispheres
schizencephaly
smaller than normal cerebellum often caused by a late gestational oral infection; usually granular layer degenerates
cerebellar hypoplasia
progressively increased lysosomal enzyme substrate due to defective enzymes or cofactors
lysosomal storage disease
gangliosidosis and lipfuscinosis are ____ _____ diseases caused by accumulation of lysosomal enzyme substrate due to defective enzymes or cofactors
lysosomal storage
when the entire brain becomes necrotic, the process is called pan-necrosis or ____; tissue becomes liquified
malacia
increasing brain volume (due to edema) within a closed space increases ______ ______
intracranial pressure
brain edema arises from _____-_____ of tissue; only contain 5% wiggle room
over hydration
the (right/left) side of this diagram displays brain edema
right
______ of brain tissue through openings of the skull can occur if edema exceeds the capacity for the cranium
herniation
herniation of the brain tissue through what structure of the cranium is the most severe?
foramen magnum
on a microscopic level, edema of the brain results in a ______ change that looks like irregular, loose vacuoles in the parenchyma
spongiform
edema arising from endothelial damage to blood-brain barrier vessels; water, proteins, and electrolytes enter the parenchyma
vasogenic edema
edema caused by intoxication of cell membrane ion pumps; intracellular water accumulation and swelling
cytotoxic edema
an example of primary cytotoxic edema where toxins from the GIT are not metabolized by the liver; causes mitochondrial swelling
hepatoencephalopathy
ventricular obstruction and or blocked CSF absorption forces CSF between ependymal cells and into brain interstitial; tissue takes up fluid from the ventricle = hydrocephalus
transependymal edema
ventricular expansion without increased CSF pressure
hydrocephalus ex vacuo
T/F: death occurs quickly in hydrocephalus patients whose brain sutures are already closed
true
an acquired tumor or congenital ependymal damage can cause
hydrocephalus
_______ of the nervous system reflects severe metabolic upset; loss of all types of nervous cells
malacia
Malacia disorders starting with the prefix ______ only affect the gray matter
polio
Malacia disorders starting with the prefix _____ only affect the white matter
Leuko
T/F: There can be resolution of malaria, but often there is gross cavitations or astroglial scars
true
can be caused by a fumonisin toxicity in horses; moldy corn poisoning
leukoencephalomalacia
Thiamine-responsive polioencephalomalacia in ruminants destroys the _____ matter of the brain
gray
Injury to the brain caused by blunt trauma; can cause permanent damage and death
concussion
Hemorrhages on the surface of the brain; can occur without cranial fractures
contusions
Physical disruption of the brain tissue; often associated with penetrating or crushing injury
lacerations
T/F: Concussions are much more common in animals than people
false
Concussions characterized by transient unresponsiveness
mild concussion
concussions where there is a loss of consciousness for 6 hours or less
classical concussion
concussion where there is diffuse axonal injury and can be acutely lethal
severe concussion
a contusion formed on the opposite side of the skull trauma site
contre coup lesion
a contusion formed on the same side of the head in which trauma occurs
coup lesion
damage with gunshot wounds to the brain is ________ to the amount of energy released in the tissue
proportional
_______ can be extradural, subdural, or parenchymal; occurs with bleeding disorders and trauma
hematoma
impaired global perfusion due to increased intracranial pressure
thromboembolic vascular disease
The most common cause of thromboembolic vascular disease
endocarditis
The _____ of the brain infant depends on the size and type of the vessel blocked, the number of arteries involved, and extent of obstruction
severity
necrosis of the gray matter in the spinal cord; commonly caused by intervertebral disk material/emboli
poliomyelomalacia
bacteria that causes thromboembolic meningiocephalitis (TEM); bacterial growth causes immune mediated vasculitis
histophilus somni
Viral infections of the endothelium can cause _____ in the brain
vasculitis
Metastatic brain tumors of _______ origin is the most common
embolic
Probability of the brain tumor metastasis is proportional to the _______ of the anatomical region
mass
Leukocyte tumors may look like ______ in the brain
inflammation
Brain tumors arising in and on the brain from local tissue
primary brain tumors
T/F: Primary brain tumors rarely metastasize outside the CNS
true
Some types of primary brain tumors can implant along pathways of _____ flow
CSF
The most common primary tumor in dogs and cats
meningioma
T/F: Surgery is often not possible for meningiomas
false
Meningiomas that are invasive are considered to be ______
malignant
______ ______ is predictive of malignancy with brain tumors
mitotic index
the most common parenchymal (intramedullary) brain tumor; usually centered in white matter
oligodendroglioma
T/F: Oligodendrogliomas usually produce excess myelin
false
The second most common parenchymal neoplasm
astrocytoma
________ are firmer, poorly defined tumors that are usually well differentiated
astrocytomas
Crumbly, soft periventricular masses; usually implant along CSF pathways
periventricular neoplasia
Tumors of Schwann cells and related cells; contained within the nerve sheath, but expand
peripheral nerve sheath tumors
expands and infiltrated pre-existing peripheral nerves
neurofibroma
tumor of the cranial nerve roots
schwanoma
malignancy of peripheral nerve sheath tumors relate to spinal cord _______ through they can also metastasize distantly
invasion
(Benign/Malignant) tumors grow rapidly in size, are anapestic, and have a high mitotic rate
malignant
(Benign/Malignant) tumors are not likely to invade the parenchyma or implant
benign
(T/F): most infections produce inflammation, but not all inflammation arises from infection
true
inflammation of the brain
encephalitis
inflammation of the spinal cord
myelitis
inflammation of the dura mater
pachymeningitis
inflammation of the Pia mater and the arachnoid layers
leptomeninges
The cerebral and meningeal vessels are the most common entryways for _____ into the brain
bacteria
_____ of bacterial etiologies directly relates to where infections localize in the brain
size
the (smallest/intermediate/large) infectious agents tend to cause choroiditis and leptomeningitis
smallest (<10 um; bacteria and yeasts)
the (smallest/intermediate/large) infectious agents tend to cause encephalitis and microabscesses
intermediate (bacterial emboli, pseudohyphae)
the (smallest/intermediate/large) infectious agents tend to cause septic infarcts and brain abscesses
large (fungal hyphae, metazoans, large emboli)
Gram (-/+) bacteria cause more rapidly progressive, more lethal meningitis
negative
bacteria that infect the leptomeninges can cause pathology int he brain which is referred to as ______ ______
supportive leptomenigitis
_______ _______ due to bacteria is the most readily visible, diffuse inflammatory lesion (LPS > iNOS > cell death)
supportive meningitis
in nearly all cases of bacterial meningitis, microscopic inflammation stops at the _____ ______
pia mater
occurs when tiny foci of inflammation coalesce over time to form a brain abscess; often follows a microembolic shower
supportive encephalitis
characterized by internal micro-abscesses and external lymphocytic meningitis; lesions are localized to the brainstem
listeriosis
most common and most dangerous type of CNS abscess
brain abscess
localized pus in the subdural space between the dura and arachnoid
empyema
true/false: antibiotic treatment for a long period of time resolves brain abscesses
false
______________ in the brain are a common result on un-treated ear infections
empyemas
fibrous tissue in the meninges that lead to encapsulation….otherwise known as?
meningeal abscess
location of viral infection lesions can be ______________ to gray or white matter separately
restricted
acute, overwhelming _________ infections cause a high viral load, cell death, and cellular inclusions
viral
DNA viruses usually cause (cytoplasmic/intranuclear) inclusions
intranuclear
RNA viruses usually cause (cytoplasmic/intranuclear) inclusions
cytoplasmic
chronic viral infections cause (less/more) viral load and more cell death and inflammation
less
viruses cause (suppurative/non-suppurative) inflammation
non
with ________________ viruses, we will observe neuronal necrosis and cell inclusions with lymphocytic inflammation
neuronotropic
with viral replication occurring in the (white/gray) matter, we will see demyelination and oligodendrocyte loss
white
with viral infections in the CNS, which is possible?
A. cell death
B. luxury function intereference
C. cytokine disregulation
D. subclinical infection
E. all of the above
E
endotheliotropic organisms cause disease by vascular damage (i.e. ___________); examples are FIP, Rickettsia, and Ehrlichia
ischemia
__________ disease can be inherited or idiopathic; either way, there is no inflammation associated with disease
prion
inherited forms of prion disease result from germ-line mutations of cellular ______ gene
PrP
prion disease results in accumulation of _____________ that is insoluble; can be transmissible
amyloid
prion disease spreads between ___________; ultimately it depends on the similarity between cellular PrP of the donor and recipient species
species
prion disease in sheep and goats that is characterized by cerebellar ataxia and wool-loss
scrapie
all prion diseases have characteristic intra-neuronal __________ and gliosis with no inflammation present
vacuoles
infected sheep produce large amounts of prion in their placentas if their lamb has a susceptible _______ genotype; infection of lambs occurs through placental/vaginal fluids at birth
prion disease of deer and elk; the environment where the affected deer die remains infectious for other animals
CWD
__________ tissue is usually infected with CWD in deer and elk prion disease (placenta less important than in sheep)
lymphoid
yes/no: is CWD in deer and elk zoonotic to people?
no
most prion diseases have some degree of ____________ formation which is thought to be the basis of their infectious nature
amyloid
fungal infections of the brain that lead to leptomeningitis, encephalitis, and infarcts
mycoses
highly pathogenic protozoa often cause ________________ within animals; causes severe inflammation (e.g. sarcocystis neurona in horses)
encephalomyelitis
organisms that cause granulomatous leptomeningitis or encephalitis; causes mild inflammation
cryptococcus
opportunistic fungi have tissue ___________ that cause parenchymal infarcts
hyphae
nematode larvae, cestode cysts, and cuterebra are all examples of ____________ infections that can cause big problems within the CNS
metazoan
immune mediated inflammation of the brain, meninges, and spinal cord; non-infectious and usually seen more in dogs
granulomatous meningoencephalitis
abnormal softening of the white matter of the brain; seen in horses with fumonisin intoxication from eating moldy corn
leukoencephalomalacia
chronic lesion secondary to brain swelling and inhibited blood flow; can be caused by an anesthetic accident
laminar polioencephalomalacia
a common injury associated with a horse “flipping over” that can cause blood and/or CSF to leak from the ear
basisphenoid fracture
collection of blood under the dura mater
subdural hematoma
how long (at least) does it take neurons to show signs of necrosis?
24 h
tumor composed of blood vessels; if hemorraged, can occupy extra space in the brain and cause increased intracranial pressure
angioma
common result of neonatal bacteremia in foals; can also be caused by an extension of an ear infection (e.g. with streptococcus)
localized meningitis
these gelatinous, multifocal lesions caused by cryptococcus fungi are called _________________
cryptococcomas
(dogs/cats) have a more inflammatory reaction to the presence of cryptococcus fungi in the brain?
dogs
cryptococcus neoformans typically infects ______________ patients
immunosuppressed
cryptococcus gattii is capable of infecting quite ______________ hosts
immunocompentant
hyphal fungal organisms frequently block blood vessels and produce septic ______________
infarts
most common brain neoplasm encountered by practitioners; presence of multiple, similar, well-defined masses in the periphery of the brain
metastatic neoplasia
true/false: metastases do not have be present in the CNS to cause neurological signs
true
this mass outside the CNS that is elevating and compressing the spinal cord can cause ___________ clinical signs
neurological
meningiomas can be operable if present on the (dorsal/ventral) aspect of the brain
dorsal
it is characteristic of __________________ that you cannot easily distinguish the edges of the tumor
astrocytomas
hydranencephaly and porencephaly result from ____ ________ necrosis (mid-gestation)
in utero
