Ch 1: Clinical Correlates pg. 1-11 Flashcards
what is anencephaly? how can it be detected during pregnancy? what are associated complications?
- cranial neuropore fails to close–>forebrain fails to develop properly
- NOT COMPATIBLE WITH LIFE
- elevated levels of alpha-fetoprotein present during amniocentesis
- pregnancy can be complicated by polyhydramnios= excess of amniotic fluid in amniotic cavity caused by the absence of the forebrain neurons that control swallowing
What results when neural crest cells fail to migrate or differentiate properly?
variety cardiac, craniofacial, or neurological defects
- neural crest cells give rise to primary sensory neurons and postganglionic autonomic neurons, which course in branches of spinal and cranial nerves
- also migrate and form many nonneuronal cell types
What can result if there is too much or too little vitamin A or a dietary deficiency of folic acid during fetal development?
can disrupt the closure of the neural tube
What is the mechanism behind fetal alcohol syndrome? What are symptoms?
- migration of neuroblasts may be disrupted, causing microencephaly (reduction in size of gyri in cerebral hemispheres)
- infant prone to mental retardation and may develop seizures and motor disorders
what is craniorachischisis totalis?
- complete failure of formation of neural tube
- most severe open neural tubr defect
what generally causes spina bifida?
- defects in the closure of the caudal neuropore
- or a failure of the neural tube to induce the surrounding mesoderm to form the neural arches of 1 or more lumbar or sacral vertebrae
what is spina bifida cystica?
cystlike protrusion through the defect in the neural arches; elevated levels of alpha-fetoprotein usually evident
what is spina bifida cystica with meningocele?
dura and arachnoid line the cyst protrusion and the cyst contains CSF
what is spina bifida cystica with meningomyelocele?
- most common form of spina bifida cystica
- dura and arachnoid line the cyst and spinal cord is displaced into the cyst
- lumbosacral spinal nerves may be stretched and newborns may have neurological deficits in lower limbs
what is rachischisis?
caudal neuropore fails to close, neural arches are absent, neural folds are exposed in the lumbosacral region
what is spina bifida occulta?
- most common closed defect (normal alpha-fetoprotein levels) and most common form of spina bifida
- defects in neural arches of lumbar or sacral vertebrae
- laminae of affected vertebrae fail to fuse in midline to form spinous processes
- tuft of hair overlying defect
telencephalon gives rise to…
2 cerebral hemispheres, preoptic area, most of basal ganglia
diencephalon gives rise to…
- thalamus, hypothalamus, epithalamus, subthalamus
- optic nerve and optic cup (including retina) are outgrowths
- posterior lobe of pituitary (neurohypophysis) outgrowth of hypothalamus
mesencephalaon gives rise to…
midbrain
metencephalon gives rise to…
pons and cerebellum
