Neuro Flashcards
Neural tube arises from
invagination of the neural plate
Neural crest cells give rise to
PNS & Schwann cells
Neuroectoderm gives rise to
CNS, ependymal cells, oligodendroglia, astrocytes
Lumen of the neural tube gives rise to
ventricles & spinal cord canal
Choroid plexus (location, produces?)
lines the ventricles & produced CSF
What structure drains CSF from the lateral ventricles to the 3rd ventricle?
Interventricular foramen of Monro
What structure drains CSF from the 3rd ventricle to the 4th ventricle?
Cerebral Aqueduct
What structure drains CSF from the 4th ventricle to the subarachnoid space?
Foramina of Magendie & Luschka
What serum marker would be elevated if there was failure of the neural tube to close?
AFP
What supplement if given prior to conception helps prevent neural tube defects?
Folate
Anencephaly pathogenesis
anterior neural tube malformation -> failure of the skull & brain (forebrain) to form
Anencephaly S/S
Open calvarium -> ‘frog-like’ appearance, polyhydramnios, high AFP
Spina Bifida pathogenesis
failure of the posterior vertebral arch to close (bony spinal canal fails to close)
Spina Bifida Occulta S/S
dimpling or hair patch over vertebral defect
Spina Bifida - Meningocele
cystic protrusion of the meninges through the vertebral defect
Spina Bifida - Meningomyelocele
cystic protrusion of the meninges & spinal cord through the vertebral defect
Cerebral Aqueduct Stenosis pathogenesis
congenital stenosis of the cerebral aqueduct leading to failure to drain CSF from 3rd ventricle to 4th ventricle
What structure signals for the formation of the neural plate?
notochord induced overlying ectoderm to differentiate into neuroectoderm -> neural plate
The notochord gives rise to
nucleus pulpous of the IV disc
What time period during embryogenesis does neural development begin?
Days 18-21: Notochord -> Induction of Neural plate -> invaginates to form Neural tube + neural crest cells
Dorsal portion of the spinal cord (alar plate) forms
sensory neurons
Ventral portion of the spinal cord (basal plate) forms
motor neurons
Microglia arise from
mesoderm
CSF is produced by
ependymal cells of the choroid plexus
What marker serves as a confirmatory test for neural tube defects?
Elevated Acetylcholinesterase (AChE) in amniotic fluid
Anencephaly Risk Factors
Maternal diabetes (type I), low folate
Neural tube defects result from the failure of ___________ during week _____
Neuropore fusion during week 4
Dandy-Walker Malformation pathogenesis
failure of the cerebellar vermis to develop -> small cerebellum + enlarged 4th ventricle
Dandy-Walker Malformation association w/
hydrocephalus, spina bifida
Arnold-Chiari Malformation (type II) pathogenesis
herniation of cerebellar tonsils & vermis through the foramen magnum
Arnold-Chiari Malformation (type II) S/S
obstructed CSF -> hydrocephalus
Arnold-Chiari Malformation (type II) is associated w/
meningocele & paralysis below
Holoprosencephaly pathogenesis
failure of the L&R hemispheres to divide
Holoprosencephaly S/S
moderate - cleft palate/lip
severe - cyclops
Holoprosencephaly may be d/t to what genetic mutation
SHH signaling pathway mutation
From what structures did the Cerebral Hemispheres arise?
Forebrain (prosencephalon) –> Telencephalon
From what structures did the Thalamus arise?
Forebrain (prosencephalon) –> Diencephalon
From what structures did the Midbrain arise?
Mesencephalon
From what structures did the Pons arise?
Hindbrain (Rhombencephalon) –> Metencephalon
From what structures did the Cerebellum arise?
Hindbrain (Rhombencephalon) –> Metencephalon
From what structures did the Medulla arise?
Hindbrain (Rhombencephalon) –> Myelencephalon
Syringomyelia pathogenesis
cystic cavity w/in the spinal cord at C8-T10, affecting the STT anterior commissural fibers
Syringomyelia S/S
pain & temp sensation loss in a “cape-like” distribution over the UEs (fine touch preserve red via DC-ML), HA, cerebellar Sx
Syringomyelia may be associated w/
Chiari type I
Sensation to the anterior 2/3 of tongue is via
CN V3
Taste to the anterior 2/3 of the tongue is via
CN 7
Taste & Sensation to the posterior 1/3 of the tongue is via
CN 9
Motor innervation to the tongue is via
CN 12
Nissl Substance stains _________ & shows up in what parts of the neuron?
RER; stains the dendrite & cell body (not axon)
Complications of Syringomyelia
Anterior horn -> LMN involvement -> muscle atrophy, weakness, low tone & reflexes
Lateral horn -> hypothalamospinal tract involvement -> Horner’s Syndrome
Anterior 2/3 of the tongue is derived from
branchial arches 1-2
Posterior 1/3 of the tongue is derived from
branchial arches 3-4
Wallerian Degeneration
axonal injury response -> degeneration distal & axonal retraction proximally
Poliomyelitis - damage to which part of the spinal cord?
Anterior motor horn
Poliomyelitis S/S
LMN signs -> flaccid paralysis, muscle atrophy, fasciculations, weakness, low tone & reflexes, Negative Babinski
Werdnig-Hoffman Disease pathogenesis
anterior motor horn degeneration (AR)
Werdnig-Hoffman Disease S/S
“floppy baby” -> death w/in a few years
Amyotrophic Lateral Sclerosis pathogenesis
sporadic, rarely familial, degeneration of the UMN & LMN Corticospinal tract
