ABP Content Specs #2: A-C: Biological Mechanisms in Development and Behaviors Flashcards
Most common congenital malformation of CNS?
neural tube defects (improper closure of the embryonic neural tube)
Anencephaly
-underdeveloped brain and incomplete skull
-most common neural tube defects
-congenital absence of brain or parts of brain and cranium
-due to failure of cranial portion of neural tube
Spina bifida?
incomplete closing of spinal cord during 3rd nad 4th week of intrauterine development
4 types of spina bifida?
- myelomeningocele: both meninges and spinal cord in efect
- meningocele: the herniation has meninges
- myelocele: defect that has herniation with only CSF fluid
- spina bifida occulta
Arnold-Chiari malformation type II
combination of myelomeningocele (meninges + spinal cord in spina bifida defect) and cerebellar tonsil herniation
Encephalocele
-rare neural tube defect in which brain protrudes through an abnormal opening of cranium with or without meninges, leaving a projection of a bag-like structure on the head
-often with hydrocephalus
-might be result of aqueductal stenosis or torsion and may also be a post-surgical completion of ecnephalocele
What gestational week for these changes?
- Neuro-ectoderm induction
third week gestation
What gestational week for these changes?
- Neurulation?
3rd to 4th week gestation
What gestational week for these changes?
- Pro-encephalic and hemispheric formation?
5-12th week gestation
What gestational week for these changes?
- Neuronal proliferation
10-12th week gestation
What gestational week for these changes?
- neuronal migration
12-24th week gestation
What gestational week for these changes?
- Programmed neuronal cell death
28-41st gestation week
What gestational week for these changes?
- Neurogenesis
15th -20th week gestation to well into postnatal months or years
What gestational week for these changes?
- Synaptogenesis
20th week gestation to puberty
What gestational week for these changes?
- Gliogenesis
20-24th week gestation to well into postnatal years
What gestational week for these changes?
- Myelination
26th-28th week gestation to 2-3 years postnatal/post-birth
What gestational week for these changes?
- Angiogenesis
5th-10th week gestation to years after birth
Direction of closure of neural tube?
rostral to caudal
Conditions you get when you get failure of closure of rostral neural tube (anterior neuro-pore)?
anencephaly or encephalocele
condition you get when you get failure of closure of caudal (posterior neuropore) neural tube?
myelo-meningo-cele
3 parts/vesicles of primitive brain?
once neural tube closed then becomes 3 vesicle structure (primitive brain) with 3 parts:
- prosencephalon
- mesencephalon
- rhombencephalon
-happens 5-6th week gestation
5 parts of primitive brain?
- forebrain/prosencephalon –> telecephalon + diencephalon –> cerebral hemispheres, thamalus –> lateral ventricles & third ventricle
- midbrain/mesencephalon –> mesencephalon –> midbrain–> aqueduct
- Hindbrain/thombencephalon –> metencephalon + myelencephalon –> pons + cerebellum + medulla –> upper part of 4th ventricle + lower part of 4th ventricle
everything else becomes spinal cord
What causes primary microcephaly?
when you don’t et enough neurogenesis
What causes classic lissencephaly?
disorder of neuronal migration