Embryology Flashcards
Notochord induces overlying ectoderm to differentiate into neuroectoderm and form the neural plate, the notochord becomes the ____ in adults.
Nucleus pulposus of intervertebral discs
Neural plate gives rise to___
neural tube and neural crest cells.
Alar plate becomes___
sensory (dorsal)
Basal plate becomes___
motor (ventral)
The three primary vesicles are?
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
The prosencephalon differentiates into which secondary vesicle(s)?
Telencephalon
Diecephalon
The mesencephalon differentiates into which secondary vesicle(s)?
Mesencephalon
The rhombencephalon differentiates into which secondary vesicle(s)?
Metencephalon
Myelencephalon
What are the adult derivatives (walls and cavities) of the telencephalon?
Walls: cerebral hemispheres
Cavities: lateral ventricles
What are the adult derivatives (walls and cavities) of the diencephalon?
Walls: thalamus, hypothalamus
Cavities: third ventricle
What are the adult derivatives (walls and cavities) of the mesencephalon?
Walls: midbrain
Cavities: aqueduct
What are the adult derivatives (walls and cavities) of the metencephalon?
Walls: Pons, Cerebellum
Cavities: upper part of 4th ventricle
What are the adult derivatives (walls and cavities) of the myelencephalon?
Walls: Medulla
Cavities: lower part of 4th ventricle.
The neuroectoderm differentiates into ____ cell types.
The neural crest differentiate into ___ cell types.
The mesoderm differentiates into ___ cell types.
Neuroectoderm: CNS neurons, ependymal cells (inner lining of ventricles - make CSF)
Neural crest: PNS neurons, Schwann cells
Mesoderm: Microglia (Macrophages)
What protein increases in amniotic fluid and maternal serum in neural tube defects (except in spina bifida occulta)?
AFP (alpha-fetoprotein)
What is a helpful confirmatory test for neural tube defects?
Increase in acetylcholinesterase (AChE) in amniotic fluid - fetal AChE in CSF flows through defect into amniotic fluid
Spina bifida occulta is ___
Failure of bony spinal canal to close, but no herniation. Dura in tact. Associated with tuft of hair or skin dimple at level of bony defect. Normal AFP.
Meningocele is __
Meninges (but no neural tissue) herniate through bony defect.
Meningomyelocele is ___
Meninges and neural tissue (cauda equina…) herniate through bony defect.
Anencephaly is ___
Forebrain anomaly.
Malformation of anterior neural tube. No forebrain, open calvarium.
Increased AFP, polyhydamnios (no swalloowing center in brain).
Associated with maternal type 1 DM.
Holoprosencephaly is ___
Forebrain anomaly.
Failure of left and right hemispheres to separate: 5-6 weeks. Maybe muts in sonic hedgehog pathway.
Moderate: cleft lip/palate. Severe: cyclopia.
Seen in Patau syndrome and FAS.
Chiari malformation is ___
Herniateion of low lying cerebellar vermis through foramen magnum. Chiari II - associated with lumbosacral meningomyelocele (paralysis/sensory loss at and below level of lesion).
Dandy - Walker Syndrome is ____
Agenesis of cerebellar vermis with cystic enlargment of 4th ventricle (fills the enlarged posterior fossa). Associated with noncommunicating hydrocephalus, spina bifida.
Syringomyelia is ___
Cystic cavity (syrinx) within central canal of spinal cord. Fibers crossing in anterior white commissure (spinothalamic tract) are typically damaged first. Results in “cape-like” bilateral loss of pain and temperature sensation. Associated with Chiari malformations, trauma, tumors.
Anterior 2/3 of tongue develops from ___ arches, with sensation via ___, and taste via ___.
1st and 2nd branchial arches.
Sensation via CNV3 (lingual n.)
Taste via CNVII (chorda tympani)
Posterior 1/3 of tongue develops from ___ arches, with sensation and taste via ___.
3rd and 4th branchial arches.
Sensation and taste: CNIX (glossopharyngeal)
Extreme posterior sensation and taste - CNX
Motor innervation of tongue via ___.
Muscle that retracts and depresses tongue ___.
Muscle that protrudes tongue ___.
Muscle that draws sides of tongue up to swallow ___.
CN XII.
Hyoglossus retracts and depresses tongue.
Genioglossus protrudes tongue.
Styloglossus draws sides of tongue upward to swallow.
