Neuro 1 Flashcards
what are the 3 classical divisions of the CNS?
- Sensorimotor division
- Autonomic division
- Enteric division
What are the 2 areas of nervous tissue in enteric division of PNS? why should we know about them?
- Myenteric plexus AKA Auerbach’s plexus
- Submucous plexus AKA Meissner’s plexus
important to understanding dysautonomias
what part of embryology gives rise to PNS?
neural crest
which of ectoderm, mesoderm, and endoderm gives rise to nervous system? what is the exception?
ectoderm
microglial cells - come from mesoderm
what cell is responsible for making myelin in the PNS?
Schwann cells
what cell is responsible for making myelin in the CNS?
oligodendrocytes
what are the 3 ways that nerves can be injured by trauma?
- transection
- compression/crushing
- stretching
Describe Wallerian Degeneration.
degeneration of the distal component of an injured axon.
the proximal segment dies back to the node of Ranvier, macrophages respond to site of injury, cell body swells b/c of chromatolysis of Nissl substance, myelinating cells guide direction of regenerating axon.
very typical response to axon injury
Why is Wallerian degeneration important in diagnosis?
can help you localize where injury occurred histologically
why is Wallerian degeneration important for disease processes?
mistakes in process can cause rein nervation of the wrong thing or proliferation of axons w/o reinnervation, which leads to formation of a neurofibroma
What are the clinical signs of equine laryngeal hemiplegia?
tall, large breeds, male, 2-7 y/o
paralysis of L side of larynx –> roaring sound during inspiration (esp. w/ exercise)
what is the other name for equine laryngeal hemiplegia?
Roarers or recurrent laryngeal neuropathy
what are the gross findings of equine laryngeal hemiplegia?
L laryngeal paralysis
neurogenic atrophy of the L dorsal, lateral, and transverse cricoarytenoid muscles
why is the L side of the larynx more affected than the R in equine laryngeal hemiplegia?
L recurrent laryngeal nerve is longer than the R
What histo lesion do we have to know for Roarers?
Wallerian degeneration of the recurrent laryngeal nerve
what are the causes of roarers?
- direct trauma to nerve
- extension of inflammation from guttural pouches
- toxins
- (inherited)
What dis?
equine laryngeal hemiplegia AKA roarers
What is the other name for Colonic Agangliosis?
Lethal white foal syndrome
what is the signalment for colonic aganliosis?
American paint horses
white foals born to parents with Overo markings.
what are the clinical signs of colonic agangliosis?
clinical signs of colic
foals die within a few days of birth
functional obstruction of GIT
what are the gross findings of colonic agangliosis?
white foal, lumen of large colon small/narrow, ileum to distal large colon affected
what histo finding do we have to know for colonic agangliosis?
lack of myenteric and submucosal ganglia
what are you worried about with this foal?
colonic agangliosis AKA lethal white foal syndrome
Diaphragmatic paralysis in camelids:
1. clinical sings?
2. gross lesions?
3. cause?
4. important ddx?
- young llamas and alpacas, resp distress
- none
- we dunno
- choanal atresia
What are the two types of Myasthenia Gravis? what species are affected?
Congenital (less common) and acquired (more common)
dogs (and less commonly cats)
in congenital myasthenia gravis, what is wrong?
defect in acetylcholine end plate receptors
in acquired Myasthenia Gravis, what is wrong?
immune-mediated antibodies against cholinesterase receptors
–> results in immune complexes of the neuromuscular junction, decreased receptor density
some cases of acquired myasthenia gravis are linked with what?
thymic abnormalities
what are the 3 clinical forms of acquired myasthenia gravis?
- generalized form: weakness of appendicular muscles with exercise, also megaesophagus
- localized form: face, esophagus, pharyngeal muscles
- fulminating form: rapidly developing and sustained weakness
what type paralysis is seen with acquired myasthenia gravis?
flaccid paralysis
what might you see at necropsy for an individual with myasthenia gravis?
megaesophagus, thymoma, or hypothyroidism
what secondary condition/cause of death might send animals with myasthenia gravis to necropsy?
aspiration pneumonia