questions 5

CNS Development

Topic updated on 05/04/17 12:02pm

  • CNS development (week 3)
    •  neuroectoderm (a subtype of ectoderm) → neural plate → brain and spinal cord 
  • Neural tube gives rise to
    • forebrain (prosencephalon) 
      • telencephalon 
        • cerebral cortex, lateral ventricles, caudate, putamen, hippocampus, olfactory bulbs
      • diencephalon
        • thalami, mammillary bodies, neurohypophysis, pineal gland, retina, optic nerve, chiasm, and tract
    • midbrain (mesencephalon)
    • hindbrain (rhombencephalon)
      • metencephalon
        • pons, cerebellum
      • mylencephalon
        • medulla
Neural tube defects
  • Failure of neuropores to fuse during week 4
    • vertebral arches do not fuse resulting in a connection between amnionic cavity and spinal canal
    • defect tends to occur in lumbosacral region
    • can be detected by testing maternal blood for ↑ α-fetoprotein (AFP)
      • if elevated and neural tube defect is present, then amniocentesis will show ↑ α-fetoprotein (AFP) and ↑ acetylcholinesterase 
    • associated with maternal folate deficiency commonly caused by: 
      • low folic acid intake during pregnancy 
      • medications that interfere with folate utilization 
        • Valproate, methotrexate, sulfasalazine, phenytoin
  • Spina bifida oculta
    • least severe variation with dura intact and no herniation
    • tuft of hair in lumbosacral region 
  • Spina bifida with meningocele
    • only meninges herniate through spinal defect forming a CSF filled sac, but spinal cord remains in spinal canal
  • Spina bifida with meningomyelocele
    • meninges and spinal cord herniate through defect


Qbank (2 Questions)

(M1.EB.6) A 24-year-old female with a history of recurrent infections, bipolar disorder, and no prenatal care gives birth to a male infant. On physical exam in the delivery room, you observe a tuft of hair over the infant's lumbosacral region. Which of the following drugs was this mother most likely taking during pregnancy? Topic Review Topic

1. Chloramphenicol
2. Gentamicin
3. Lithium
4. Valproate
5. Folic acid

(M1.EB.4753) A 25-year-old G1P1 with a history of diabetes and epilepsy gives birth to a female infant at 32 weeks gestation. The mother had no prenatal care and took no prenatal vitamins. The child’s temperature is 98.6°F (37°C), blood pressure is 100/70 mmHg, pulse is 130/min, and respirations are 25/min. On physical examination in the delivery room, the child’s skin is pink throughout and he cries on stimulation. All four extremities are moving spontaneously. A tuft of hair is found overlying the infant’s lumbosacral region. Which of the following medications was this patient most likely taking during her pregnancy? Topic Review Topic

1. Lithium
2. Ethosuximide
3. Warfarin
4. Gentamicin
5. Valproic acid

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