Neurodevelopment Flashcards
Morula is the solid ball fo cells formed as the zygote undergoes ???
cleavage
early or late (?) blastocyst is a hollow ball of cells with a fluid-filled caivty
early blastocyst
early or late (?) blastocyst is pre-embryo with embryonic disk, two layers of cells that become the embryo proper
late blastocyst
primary germ layers: the ectoderm gives rise to ???
skin and nervous tissue
gastrula is the embryo with ??? primary germ layers
3 primary germ layers
primary germ layers: the endoderm gives rise to ???
viscera
primary germ layers: mesoderm gives rise to ???
muscles and bones
Neurulation occurs at ??? gestational days
~22 days
Neurulation: a longitudinal band of ??? thickens to become the neural plate
ectoderm
differential division rates cause upward folding of plate to become ??? –> neural tube
neural fold
lateral border of the neural fold becomes the neural ???
crest
the neural tube later forms into the ???
CNS
dorsal ectoderm of gastrual forms ???
neural groove
if the neural tube does not close together, this causes neural tube defects. i.e. anencephaly due to failure of ANTERIOR or POSTERIOR neuropore to close?
Anterior
Anencephaly: brain is not formed, ??? may be absent, facial abnormalities, neonatal death is inevitable.
skull
failure of ANTERIOR or POSTERIOR neuropore to close = spina bifida
posterior
Spina Bifida is a condition in which malformations of the spinal cord occur, characterised by failure of one or more ??? arches to meet and fuse
vertebral
Spina Bifida Occulta or Cystica is when spinal cord + meninges are unharmed and remain within the vertebral canal. Common site = lumbosacral area, and usually associated with no disturbance of neurological or musculoskeletal functioning
Pina Bifida Occulta
SB Cystica, Meningocele or Myelomeningocele: Cystic protrusion of meninges and CSF through defective vertebral arches. Spinal cord remains in the vertebral canal. May still exhibit some abnormalities. Clinical signs vary or may be absent
Meningocele
SB Cystica, Meningocele or Myelomeningocele: Majority of SB cases. Cystic protrusion of spinal cord, meninges and CSF through defective vertebral arches. Open myelomeningocele: nerve roots and spinal cord may be exposed
Myelomeningocele
SB complications include:
- ??? ‘water on brain’
- spinal tethering
- Chiari Malformation
hydrocephalus
chiari malformation ocurs when brainstem and/or cerebellum is pushed down through opening of brain, compressing the brainstem, lower cerebellum = obstruction of ??? flow
CSF.
note: this is also known as tonsillar herniation
Syringomyelia/ Syringobulbia = fluid filled cyst (syrinx)
this is a complication of ???
SPina Bifida
Folic acid is essential for synthesis of ??? i.e. when cells divide
DNA/RNA
??? deficiency is a risk factor for neural tube defects.
Folic Acid
the ??? is a neural inducer that is made of mesodermal tissue and sits under the neural plate
notochord
the notochord arise at ~16 gestational days, and is ??? (i.e. not in adults)
transient
Notochord activates/ represses developmental (homeobox) genes (transcription factors) in the ???
neural plate
the ??? stimulates synthesis of growth fators that are produced in a gradient, causing differential growth rates of neural tissue
notochord
the ectoderm produces ??? protein which, early in development, inhibits the formation of neural tissue
bone morphogenetic protein
the notochord releases ??? and cordin which inhibit bone morphogenetic protein and induce neural tissue
noggin
the notochord releases sonic hedgehog, a growth factor which causes a dorsal ventral separation of the neural tube and induces ??? neuron formation
motor neuron
when released in a gradient from ROOF PLATE of neural tube or ECTODERM (?), bone morphogenetic protein induces dorsal sensory neuron formation
ROOF PLATE of neural tube