Ch 1: Clinical Correlates pg. 1-11 Flashcards Preview

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Flashcards in Ch 1: Clinical Correlates pg. 1-11 Deck (21)
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1
Q

what is anencephaly? how can it be detected during pregnancy? what are associated complications?

A
  • 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
2
Q

What results when neural crest cells fail to migrate or differentiate properly?

A

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
3
Q

What can result if there is too much or too little vitamin A or a dietary deficiency of folic acid during fetal development?

A

can disrupt the closure of the neural tube

4
Q

What is the mechanism behind fetal alcohol syndrome? What are symptoms?

A
  • 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
5
Q

what is craniorachischisis totalis?

A
  • complete failure of formation of neural tube

- most severe open neural tubr defect

6
Q

what generally causes spina bifida?

A
  • 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
7
Q

what is spina bifida cystica?

A

cystlike protrusion through the defect in the neural arches; elevated levels of alpha-fetoprotein usually evident

8
Q

what is spina bifida cystica with meningocele?

A

dura and arachnoid line the cyst protrusion and the cyst contains CSF

9
Q

what is spina bifida cystica with meningomyelocele?

A
  • 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
10
Q

what is rachischisis?

A

caudal neuropore fails to close, neural arches are absent, neural folds are exposed in the lumbosacral region

11
Q

what is spina bifida occulta?

A
  • 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
12
Q

telencephalon gives rise to…

A

2 cerebral hemispheres, preoptic area, most of basal ganglia

13
Q

diencephalon gives rise to…

A
  • thalamus, hypothalamus, epithalamus, subthalamus
  • optic nerve and optic cup (including retina) are outgrowths
  • posterior lobe of pituitary (neurohypophysis) outgrowth of hypothalamus
14
Q

mesencephalaon gives rise to…

A

midbrain

15
Q

metencephalon gives rise to…

A

pons and cerebellum

16
Q

myelencephalon gives rise to…

A

medulla

17
Q

what is an encephalocele?

A

meninges, meninges+part of CNS, or meninges+CNS+part of ventricular system herniates through a defect in the skull (most commonly occipital region)

18
Q

what are Arnold-Chiari I malformations? what age is it commonly seen?

A
  • result from a congenital herniation of the tonsils of the cerebellum inferiorly through the foramen magnum–>may compress the medulla or cervical spinal cord
  • young adults
19
Q

what are Arnold-Chiari II malformations? what age is it commonly seen?

A
  • result from herniation of the cerebellar vermis

- neonates

20
Q

what is Dandy-Walker syndrome?

A

congenital defects in the development of the vermis of the cerebellum, and the foramina of Luschka and the foramen of Magendie in the 4th ventricle fail to open

21
Q

what can happen to a patient with Arnold-Chiari malformation and Dandy-WAlker syndrome?

A

noncommunicating hydrocehalus