Trans - Neuroembryology Flashcards
when does the primitive streak appear
day 15
when does the neural tube appear
day 22
when does the neural fold appear
day 20
germ layer precursor of CNS
ectoderm
result of rostral neural tube growth
brain
result of caudal neural tube growth
spinal cord
fusion of the neural folds begins in what region
cervical
what region of the spine is the oldest
cervical spine
neuroectodermal cells that are not incorporated into the tube during the course of development
neural crest cells
neural crest cells may differentiate into:
ganglion cells
ganglion - define
cluster of neuron soma found outside the brain and spinal cord
what neuropore closes first
anterior neuropore
when does the brain have 3 primary segments
3rd week of development
when does the brain have 5 secondary segments
7th week of development
immediate fate of prosencephalon
becomes telencephalon and diencephalon
immediate fate of mesencephalon
remains mesencephalon
immediate fate of rhombencephalon
becomes metencephalon and myelencephalon
precursor of cerebrum
telencephalon
precursor of thalamus and hypothalamus
diencephalon
precursor of midbrain
mesencephalon
precursor of pons and cerebellum
metencephalon
precursor of medulla
myelencephalon
first flexure to appear
cervical flexure
cervical flexure is between
rhombencephalon and spinal cord
cephalic flexure is between
prosencephalon and mesencephalon
how are the cerebral hemispheres formed
evaginations of telencephalon
peak time period of neuronal proliferation
3-4 months into gestation
proliferation starts with what type of cell
primitive ectodermal cell
how are proliferative units formed
symmetrical divisions
how are proliferative units modified
asymmetical divisions
primitive neuroectodermal blast cells may differentiate to become:
- neuroblast
- glioblast
- ependymoblast
peak time period of neuronal migration
3-5 months into gestation
how do cells migrate to form the cerebrum
radial migration
how do cells migrate to form the cerebellum
radial migration and tangential (sideward) migration
cytoarchitectonic organization is based on:
cell types
myeloarchitectonic organization is based on:
myelin staining
layer with the most number of neurons
external pyramidal
layer with the biggest neurons
internal pyramidal
layer with small pyramidal cells
external granular
layer with stellate cells
internal granular
layers important in the primary motor cortex
3 and 5
internal pyramidal and external pyramidal
layers important in the primary sensory cortex
4 – internal granular
layers important in receiving impulses
2 and 4
external and internal granular
layer important in visual cortex
4 – internal granular
layer forming line of Gennari
4 - internal granular
other name for line of Gennari
internal band of Baillarger
how many layers are there in the hippocampus, and what are they
- molecular
- pyramidal
- multiform
how many layers are in the cerebellum, and what are they
- molecular
- purkinjie
- granular
which are outer in the cerebellum, stellate or basket cells
stellate cells
concentric layers of spinal cord
- ependymal layer
- mantle layer - gray matter
- marginal layer - white matter
why is the arrangement of gray matter and white matter different in the brain and in the spinal cord
different rates of migration
brain neurons migrated from paraventricular area all the way outward, spinal cord neurons did not
basal plate - motor or sensory
motor
alar plate - motor or sensory
sensory
separates basal and alar plates
sulcus limitans
peak time period of neuronal organization
5 months into gestation
peak time period of myelination
birth to postnatal
portions of meninges and spinal cord protrude through an abnormal cleft in vertebral arch caused by incomplete closure of neural folds
myelomeningocoele
cerebellar herniation through spinal cord
Arnold Chiari malformation
absence of brain and calvaria
everyone’s favorite anencephaly
characterized by anencephaly and total spina bifida
craniorachischisis totalis
caudal portion of neural tube fails to form
myeloschisis
failed or incomplete forebrain separation with facial deformity
holoprosencephaly
caused by abnormally slow proliferation
microcephaly vera
caused by abnormally fast proliferation
macrocephaly vera
schezencephaly - define
cleft of white matter on cortex
lissencephaly - define
no gyri
pachygyra - define
large cerebral folds
micropolygyra - define
small, numerous gyri
heterotropia
gray matter left behind in subcortical white matter
primary disturbance
connections are not well formed
dysmyelination
myelin sheath does not form
demyelination
myelin sheath forms but is destroyed / damaged