Neurology Flashcards
Which organ is a specialized ganglion in which the preganglionic fibers innervate this organ directly?
Adrenal medulla - Preganglionic fibers innervate the chromaffin cells directly.
What hormones does the adrenal medulla secrete (and in what proportion)?
Epinephrine (80%)
Norepinephrine (20%)
Where are nicotinic receptors located?
- Autonomic ganglia (sympathetic and parasympathetic)
- Neuromucular junctions
- Adrenal medulla
Where are muscarinic receptors located?
- Heart
- Smooth muscle
- Glands
What are the three type of glial cells?
- Astrocytes
- Oligodendrocytes
- Microglial cells
What are astrocytes?
Supply metabolic fuels for neurons, secrete trophic factors and synthesize neurotransmitters
What are oligodendrocytes? What about Schwann cells?
Synthesize myelin in the CNS. Schwann cells synthesize myelin in the PNS.
What are microglial cells?
Proliferate following neuronal injury - scavenge for cellular debris
What are first-order neurons in the sensory pathway?
Primary afferent neurons that receive transduced signal and transmit it to the CNS.
Cell bodies in the dorsal root or spinal cord ganglia
What are second order neurons?
Located in spinal cord or brainstem - Transmit info from first order neurons to the thalamus (cross the midline).
What are third order neurons?
Relay sensory info from thalamus to cerebral cortex
What are fourth order neurons?
The received information results in a conscious perception of the stimulus
What retinal cells are better for night vision?
Rods
What retinal cells are better for color vision?
Cones
What decussates at the optic chiasm?
Neurons from the nasal hemiretina on each side.
What organ contains receptor cells for auditory stimuli?
Organ of Corti - inner ear
Lesions of what structures lead to paradoxical vestibular syndrome?
Cerebellum - Floculonodular node or caudal cerebellar peduncle
With paradoxical vestibular syndrome, what direction is the head tilt? What side postural reactions are affected?
- Head tilt is away from the lesion
2. Postural reaction deficits are ipsilateral
True or false - Paradoxical vestibilar syndrome is alway central.
True - Specifically cerebellum (floculonodular lobe, caudal cerebellar peduncle)
What are seizures?
Synchronized discharges are generated by the grey matter of the cerebral cortex
Do forebrain lesions affect gait?
No - The generators of gait are below the thalamus
In vestibular disease, the head tilt is (towards/away) the lesion and the fast phase of nystagmus is (towards/away) from the lesion.
Head tilt towards the lesion
Nystagmus fast phase away from the lesion
What are medical treatments for congenital hydrocephalus?
Acetazolamide/omeprazole - dec CSF production
Glucocorticoids
What are surgical treatments for congenital hydrocephalus? Prognosis?
Ventriculoperitoneal shunt - 85% have long term improvement
How does surgical treatment of meningioma for dogs vs cats vary in terms of prognosis?
Feline - Sx may be curative
Dogs - Debulk (Sx often not curative) + radiation/chemo
How does hypercapnia affect cerebral bloodflow?
Causes vasodilation
What is gabapentin’s MOA?
Inhibition of voltage-gated Ca++ channels
Phenobarbital MOA
Gaba-chloride channel
Which anticonvulsant has been associated with blood dycrasias?
Phenobarb - bone marrow toxicity, pancytopenia, d/c pheno fast and should see improvement
How is pregabalin (Lyrica) similar to gabapentin?
Greater affinity for α2δ-subunit of voltage-gate Ca channels than gabapentin
More effective as both analgesic and anticonvulsant
Which is the only anti-epileptic drug that is specifically approved for dogs in the US?
Primidone
What is Keppra’s MOA?
Inhibits to SV2A (Calcium channel blocker)
How does phenobarbital affect the metabolism of Keppra?
Phenobarb increases Keppra’s metabolism
What is Zonisamide’s MOA
Blocks T-type Ca and voltage gated Na channels in the brain,
facilitates dopaminergic and serotonergic neurotransmission,
free radical scavenging,
enhancing GABA activity,
inhibition of glutamate,
and inhibition of carbonic anhydrase
What is a potential side effect of zonisamide?
Hepatotoxicity
What medications can cause PERIPHERAL vestibular signs?
Aminoglycosides, furosemide, chlorhex topical ear cleaning solutions
What endocrinopathy can cause peripheral vestibular signs?
Hypothyroidism
What medication can cause CENTRAL vestibular disease?
Metronidazole
What gene is associated with degenerative myelopathy
SOD1 - Superoxide desmutase
AA lux in small breed dogs is usually (congenital/acquired)
Congenital - malformation of the dens of the atlas
AA lux in large breed dogs is usually (congenital/acquired)?
Acquired - trauma
What is the signalment for osseous Wobbler’s?
Young, giant breed dog (great danes)