Development

Question 1

schizencephaly

Answer 1

b/c of errors in cellular migration

clefting of cerebral cortex; cortex is thin or absent

Question 2

lissencephaly

Answer 2

b/c of errors in cellular migration

absence of gyri, smooth cerebral surface, cortex is abnormal microscopically

Question 3

pachygyria

Answer 3

b/c of errors in cellular migration

abnormally large gyri due to incomplete formation

Question 4

heterotopia

Answer 4

b/c of errors in cellular migration

abnormal accumulation of cortical neurons found in white matter (abnormal migration) or near ependyma of ventricles (failure to migrate)

Question 5

callosal agenesis

Answer 5

b/c of errors in cellular migration

partial or complete absence of corpus callosum

Question 6

anterior commissure connects

Answer 6

olfactory bulbs and temporal lobes

Question 7

commissure of fornix connects

Answer 7

hippocampal formations

Question 8

corpus callosum connects

Answer 8

non-olfactory cortical areas of right and left cerebral cortices

Question 9

what DOES NOT connect the hemispheres

Answer 9

posterior commissure (connects pretectal area) and habenular commissure (connects habenular nuclei)

Question 10

encephalocele

Answer 10

neural tube deficit -> failure of cranial neuropore to close

midline defects in formation of cranium due to abnormal closure of neural tube allowing herniation of CNS (most likely occipital area in midline)

Question 11

anencephaly

Answer 11

neural tube deficit -> failure of cranial neuropore to close

absence of brain and cranial vault

Question 12

meroanencephaly

Answer 12

neural tube deficit -> failure of cranial neuropore to close

absence of brain and cranial vault w/ rudimentary brain steam and some functional brain tissue

Question 13

spina bifida

Answer 13

neural tube defecit -> failure of caudal neuropore to close

-oculta: defect in fusion of vertebral arch of L5 or S1

• cystica: protrusion of meninges and/or neural tissue through defect in vertebral arch to form a cyst-like sac
• w/ meningocele: meningeal cyst or sac contains meninges and CSF but no spinal cord tissue
• w/ meningomyelocele: more common; spinal cord or roots are included in sac w/ disorganization of neurons; muscle weakness or paralysis below spinal cord level and loss of sensation
• w/ myelocele (myeloschisis): spinal cord is open b/c neural folds fail to fuse (cauda neuropore remains open)