Flashcards in Neurology - Embryology Deck (41)
What is the function of the notochord?
Inducing overlying ectoderm to differentiate into neuroectoderm, and form the neural plate -> give rises to the neural tube and neural crest cells
What is the adult remnant of the notochord?
Nucleus pulposus of the intervertebral disc
What is the alar plate?
What is the basal plate?
When is the neural tube formed?
Day 18-21 (3 weeks)
What are the three primary vesicles of the developing brain?
What are the five secondary vesicles of the developing brain?
Adult derivative of: telecephalon
Adult derivative of: diencephalon
Adult derivative of: mesencephalon
Adult derivative of: metencephalon
Pons and Cerebellum
Upper part of the fourth ventricle
Adult derivative of: myelencephalon
Lower part of the fourth ventricle
When does neural tube defects occur?
What is neural tube defects associated with?
low folic acid
What lab values suggest neural tube defect?
What is a confirmatory test for neural tube defect?
Spina bifida occulta
failure of bony spinal canal to close
no structural herniation, usually lower vertebral level; dura is intact
associated with tuft of hair or skin dimple
Meninges (but not spinal cord) herniate through spinal canal defect
Meninges and spinal cord herniate through spinal defect
Malformation of anterior neural tube - no forebrain, open calvarium (frog-like appearance)
Lab values for anencephaly
High AFP, polyhydramnios (no swalloing center)
What is anencephaly associated with?
materal diabetes (Type I)
What can decrease risk of anencephaly?
maternal folate supplement can decrease risk
Failure of left and right hemispheres to separate; usually weeks 5-6
What is suggested to be mutated in holoprosencephaly?
sonic hedgehog signaling pathway
What are moderate and severe forms of holoprosencephaly associated with?
cleft lip/palate - moderate
cyclopia - severe
Cerebral aqueduct stenosis
Accumulation of CSF in ventricular space - most common cause of hydrocephalus in newborns
Presentation of cerebral aqueduct
enlarging head circumference due to dilation of ventricles (cranial suture lines not fused)
What is dandy-walker malformation?
Congenital failure of cerebellar vermis to develop
Massively dilated 4th ventricle with absent cerebellum often accompanied by hydrocephalus