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Embryo 3
Neurulation
44
Veterinary Medicine
Not Applicable
04/10/2017

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Term
What is neurulation?
Definition
transformation of the ectoderm into nervous tissue, to form a neural tube
Term
Neurulation is induced by the...
Definition
notochord aka chordamesoderm
Term
Neurulation happens at ___ weeks post-fertilization
Definition
3 weeks
Term
True or False

The notochord up-regulates expression of BMP-4 to promote neural plate formation
Definition
false

The notochord INHIBITS BMP-4 using molecules such as Noggin and Chordin, which allows the neural plate to form
Term
What is BMP-4?
Definition
a gene involved with epidermal expression. it needs to be down-regulated in order for the neural plate to form
Term
What are the steps of neurulation
Definition
1. Ectoderm thickens forming neural plate
2. Edges of plate raise forming neural folds
3. Lateral edges of plate come together forming neural tube
4. Tube separates from ectoderm, which fuses above the tube
5.Tube forms cranially & caudally until anterior & posterior neuropores close
Term
What molecules are neural inducers?
Definition
noggin & chordin
Term
Where does neural tube formation start?
Definition
cervical region
Term
When does neural tube formation stop?
Definition
when anterior & posterior neuropores close
Term
What are neural crest cells?
Definition
cells between neural plate & surface ectoderm, will form PNS, melanocytes, head/neck structures etc
Term
The _____ allows the neural plate to fold inward, while the _____ allow it to converge in the midline. This is facilitated by what protein?
Definition
median hinge point - inward

dorsolateral hinge points (2) - form bend at the crest of the 'wings'

F-actin
Term
Cellular basis for neural induction
Definition
F actin mediates change in shape of cells at the median & dorsolateral hinge points, so they are bottle shaped facilitating the bending
Term
Prior to folding, the neural plate expresses transcription factors ____ and ___
Definition
Pax-3 & Pax-7
Term
What gene induces the median hinge point?
Definition
sonic hedgehog (shh)
Term
What gene is involved with giving neural crest cells their ability to migrate easily?
Definition
snail-2
Term
Ventrally, ____ suppresses expression of Pax-3 & Pax-4, while ____ promotes their exression dorsally, allowing the tubular shape to form.
Definition
shh suppresses ventrally

Wnt & WMP promote dorsally
Term
the PNS is derived from 3 sources, what are they and what do each give rise to?
Definition
-neural crest cells (postganglionic ANS)
-neural tube (preganglionic ANS, skeletal motor neurons)
-mesoderm (duramater, CT of nerves)
Term
What is secondary neurulation?
Definition
-caudal to posterior neuropore

-rod of mesenchymal cells form a rod
-cavitation creates a central canal
-canal becomes continuous with canal from primary neurulation
Term
_____ neurulation contributes to tail formation
Definition
secondary
Term
The marginal layer of the neural tube forms _____ matter of CNS
Definition
white matter of CNS
Term
The mantle layer of the neural tube forms ____ matter of the CNS
Definition
grey
Term
The _______ layer of the neural tube gives rise to neuroblasts
Definition
ventricular
Term
2 layers of the mantle/intermediate layer of the neural tube. sensory or motor?
Definition
alar plate - dorsal, sensory
basal plate - ventral, motor
Term
Derivatives of neural crest cells

DASMOM
Definition
DASMOM

-dorsal root ganglia
-autonomic ganglia
-schwann cells
-melanocytes
-odontoblasts
-mesenchyme
Term
3 major groups of neural crest cells
Definition
cranial
circumpharyngeal
trunk neural crest
Term
Preganglionic neurons of the SNS and PSNS originate from the...
Definition
basal plate of the mantle layer
Term
Postganglionic neurons of the SNS and PSNS originate from the....
Definition
neural crest cells
Term
True or False

The posterior region of the neural tube develops into the brain
Definition
false

anterior
Term
Primary brain vesicles are formed by the ___ week
Definition
4th
Term
3 primary brain vesciles
Definition
prosencephalon
mesencephalon
rhombencephalon
Term
Divisions of the prosencephalon and what they give rise to
Definition
telencephalon (cerebral cortex)
diencephalon (thalamus/hypothalamus)
Term
Midbrain comes from what primary brain structure..
Definition
mesencephalon
Term
Divisions of the rhombencephalon
Definition
metencephalon (pons & cerebellum) and myelencephalon (medulla oblongata)
Term
What cells produce CSF in the brain?
Definition
choroid plexus
Term
Where are lateral ventricles of the brain formed?
Definition
telencephalon
Term
Where is the 3rd ventricle of the brain formed?
Definition
diencephalon
Term
Where is the fourth ventricle of the brain formed?
Definition
rhombencephalon (metencephalon & myelencephalon)
Term
the 3rd & 4th ventricles are connected via the...
Definition
aqueduct
Term
What is anencephaly
Definition
when the anterior neuropore of the neural tube fails to close
Term
What is spina bifida?
Definition
when the posterior neuropore of the neural tube fails to close
Term
What is waardenburg syndrome?
Definition
neurocristopathy characterized by white patches of hair due to failure of melanocytes to migrate. May also see very pale blue eyes or heterochromic eyes
Term
Albinism is due to....
Definition
neurocristopathy
Term
Meningocele
Definition
spini bifida with the meninges protruding
Term
myelomeningocele
Definition
spina bifida with the meninges and the spinal cord itself protruding
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