Central Nervous System Flashcards
in the brain, where is the grey matter and where is the white matter?
grey matter is on the outside and white matter is on the inside
what are the two functions of astrocytes?
- repair (glial scar)
- support and important component of the BBB
what is the function of oligodendroglia?
myelinating cells within the CNS
what is the function of microglial cells?
phagocytic cells of the CNS
how do neuronal cell bodies respond to degeneration within axons?
chromatolysis
what do injured axons undergo?
Wallerian degernation
what are the 2 astrocytes that he wanted us to know for the exam?
gemistocytic astrocytes and Alzheimer’s type II astrocytes
what are the two types of demyelination?
- primary - due to loss of oligodendrocytes
- secondary - due to loss of axons (most common)
what type of brain edema is the most common and is due ti extracellular fluid accumulation? what is the underlying mechanism?
vasogenic edema
underlying mechanism is a breakdown of the BBB
what type of brain edema is due to the accumulation of intracellular fluid in the neurons, astrocytes, oligodendroglia, and endothelial cells?
cytotoxic edema
what type of brain edema is elevated ventricular hydrostatic pressure?
hydrostatic edema
when does hypo-osmotic edema occur?
after the over-consumption of water (water intoxication)
what is it called when the brain has no gyri?
Lissencephaly
what in-utero viruses an cause cerebellar hypoplasia in calves, kittens, puppies, and piglets?
calves - pestivirus (BVD)
kittens - panleukopenia virus
puppies - canine parvovirus
piglets - classic swine fever virus
what are the two types of hydrocephalus? which is the most common?
communicating (more common) and non-communicating (due to obstruction)
what it is called when there is an abnormal dilation of the central canal of the spinal cord that leads to the formation of a cavity in which CSF may accumulate?
hydromyelia
what is it called when there is a fluid filled cyst within the spinal cord separate from the central canal and not lined by ependymal cells?
Syringomyelia
what are the 3 portals of entry to the CNS?
- direct extension (from inner ear, nasal sinuses through the cribriform plate or bones)
- hematogenous
- retrograde axonal transport (rabies and listeria)
what bacteria can cause brain abscesses?
streptococcus, E. coli, staphylococcus, Corynebacterium, Klebsiella
if you have meningitis in a calf, what is the most likely cause?
most likely streptococcus or e. coli secondary to an umbilical infection, which goes septic
what two viruses cause ganglioneuritis?
rabies or herpesvirus
what virus has no gross lesions but non suppurative encephalitis is present histologically?
Rabies
what fungi has a particular affinity for the CNS, and enters the leptomeninges and subarachnoid space by direct extension through the cribriform plate? How does it protect itself from host defenses?
Cryptococcus neoformans
has a thick mucinous capsule
what parasite causes feline ischemic encephalopathy?
Cuterebra larva
what is the most common toxicosis in cattle? what does it cause? what should be sampled?
Lead poisoning
causes polioencephalomalacia
sample fresh liver and stomach contents
if you have polioencephalomalacia, but no lead toxicosis, what is your next suspected condition? What should you see?
Salt toxicity
histologically should see eosinophilic meningoencephalitis
what is the pathogenesis of tetanus? what will you see upon necropsy?
Clostridium tetani releases tetanospasmin (toxin), which is transported by retrograde axoplasmic flow. The toxin blocks the release of inhibitory neurotransmitters like glycine and GABA
no gross or histology lesions
what bacteria causes flaccid paralysis of muscles by blocking the release of ACh and causes no gross or histological lesions?
Clostridium botulinum (botulism)
Leukoencephalomalacia (moldy corn disease) is caused by what fungus and causes what?
Fusarium moniliforme
necrosis of the white matter of the brain
what is the tumour called of the young animal brain in the roof of the fourth ventricle? Why is it significant even if it is benign?
medulloblastoma
compresses the brain stem, any space occupying lesion of the brain is problematic (no room for fooling around)
what tumour of dogs involves the pyriform lobe?
astrocytoma
what type of brain tumours look like an “O” and are well demarcated?
Oligodendrogliomas
what is the most common intracranial tumour of cats? Where is it located?
Meningioma
tumour on top of the brain
what is the ruminant silage disease? Where do the lesions occur?
Listeria monocytogenes
medulla oblongata and pons
what disease is seen in adult sheep, causing non-suppurative encephalitis with primary demyelination? What is the causative virus?
Maedi-Visna
Lentivirus
what disease of young goats causes CNS signs and arthritis in older goats that survive? what is the causative virus?
Caprine Arthritis Encephalitis
Lentivirus
what are the 4 causes of polioencephalomalacia?
- lead poisoning
- Salt toxicity
- high water sulfur
- thiamin deficiency
if you have a case of polioencephalomalacia that isn’t lead or salt toxicity, what is your next guess? Where would you check?
High water sulfur, test the water source
what are the two syndromes of sheep and goats that are associated with copper deficiency?
- swayback - congenital form
- enzootic ataxia - delayed form, seen at 6 months after birth
