Neuro 1 Flashcards
Holoprosencephaly
• associated anomalies
• caused by
- Failure of forebrain to divide into cerebral hemispheres
- Associated with cyclopia and facial anomalies
** loss of midline structure
Cause:
- Ewe eats plant -Veratrum californicum on DAY 14
- must be other causes bc we see this sometimes
(in humans – Fetal alcoholism, Morning after pill)
Encephaloclasic defects (2 forms)
• what species mainly
• caused by
• mainly ruminants
continuum of dz
- Porencephaly -smaller
- Hydranencephaly -larger
always fetal dz
- *start as necrosis of parenchyma of the brain
- liquifactive necrosis of white matter –> partial to total loss of brain
Main causes:
- Viral – BVD, bluetongue
Ventricular dilation
How can you tell if it is congenital?
Accumulation of CSF in ventricular system Causes: - Obstruction of outflow - decreased absorption - Excess production
Can be congenital or acquired
-Congenital –> enlargement of calverium due to lack of closure!
Hydromyelia
Dilation of central canal of spinal cord
- -Congenital or acquired
- Still lined by ependymal cells
Syringomyelia
- Tubular cavitation in spinal cord
- May communicate with central canal, but NOT lined by ependymal cells
- Syringo- = Tube/fistula
Cerebellar hypoplasia
Link to viral destruction of external granular layer
- Feline panleukopenia
- BVD virus
• they like rapidly dividing cells
Dysraphism / Meningocele
Protrusion of meninges through defect in dorsal aspect of cranium or vertebral column
• covered just by skin or meninges
• sometimes brain/spinal cord can come thru with it
** Raph- = “seam”
Meningoencephalocele
brain + meninges protrude thru dorsal cranium
Meningomyelocele
spinal cord + meninges protrude thru dorsal cranium
Colonic aganglionosis
‘Overo lethal white foal syndrome’
• American Paint horse foals
= Unpigmented hair and skin
- 1 AA mutation in Endothelin receptor B gene
- -> lack signal of Neural crest stem cell
- -> into Lg intestinal ganglia & lack of Melanocytes
- -> mechonium stays in GI tract
- -> death from intestinal obstruction
Name the types of glial cells
- Macroglia
- astrocytes
- oligodendroglia - Ependymal cells /choroid plexus
- Microglia
- derived from Monocytes
Neuropil
term for Cellular Processes of neurons and glia that compose the GRAY matter of the brain/cord
Leptomeninges
Arachnoid membrane & pia mater + space btwn
-Ruminants often have Melanosis
Nissl substance
- the predominant cytoplasmic feature of most neuronal cell bodies
- granular/ smudged basophilic material
- RER & polysomes
**not in axons!
What do you call a “group of neuronal cell bodied in the CNS”?
What are axons called?
Nuclei
Tracts – named for sites of origin and termination
What do you call a “group of neuronal cell bodied in the PNS”?
What are axons called?
Ganglia
Nerves
- UMN axons = confined to the CNS
- extend to neurons in the brain stem and spinal cord - LMN extend from cell bodies in the brain stem or spinal cord into cranial nerves and spinal nerves of the PNS