Flashcards in Embryology II Deck (22)
When are the neuropores expected to fuse together?
At the fourth week of gestation (p.409)
What occurs if the neuropores do not fuse together at the fourth week of gestation?
Neural tube defects (p.409)
What is a neural tube defect?
A persistent connection between the amniotic cavity and spinal canal (p.409)
What amniotic fluid and maternal serum protein is elevated in the instance of a neural tube defect?
Elevated a-fetoprotein (AFP) (p.409)
What amniotic protein is used to confirm a neural tube defect in a fetus?
Elevated acetylcholinesterase (p.409)
What is spina bifida occulta?
Failure of the spinal canal to close without structural herniation; dura is intact (p.409)
Where is spina bifida occulta usually seen?
At the lower vertebral levels (p.409)
What physical findings are associated with spina bifida occulta?
A tuft of hair or skin dimple at the level of the bony defect (p.409)
What is a meningocele?
When the meninges (but not the spinal cord) herniate through the spinal canal defect (p.409)
What is a meningomyelocele?
When the meninges and spinal cord herniate through the spinal canal defect (p.409)
Name three neural tube defects.
Spina bifida occulta, meningocele, meningomyelocele (p.409)
Name two forebrain embryologic anomalies.
Anencephaly, holoprosencephaly (p.409)
What is anencephaly?
Malformation of the anterior neural tube resulting in no forevrain and open calvarium (p.409)
What are the clinical findings associated with anencephaly?
Increased a-fetoprotein, polyhydraminos (no swallowing centre in the brain) (p.409)
What maternal condition is associated with anencephaly?
DM type I (p.409)
What can decrease maternal risk of a fetus with anencephaly?
Folate supplementation (p.409)
What is holoprosencephaly?
Failure of left and right hemispheres to separate (p.409)
When does holoprosencephaly occur in a fetus?
During weeks 5-6 (p.409)
What is the etiology of holoprosencephaly?
Multifactorial; may be related to mutations in sonic hedgehog signaling pathway (p.409)
Name a common clinical finding associated with mild holoprosencephaly.
Cleft lip/palate (p.409)
Name a common clinical finding associated with severe holoprosencephaly.