Neuroembryology Flashcards
from what cell layer does the CNS arise?
ectoderm
from what cell layer does the notochord arise?
mesoderm
what does the notochord induce the ectoderm to differentiate into?
neural crest cells
neural plate
when does neurulation begin
week 3
what is the adult remnant of the notochord?
nucleus pulposus
what are are developmental stages of the neural plate and what induces these changes
neural plate => neural groove => neural tube
INDUCED BY NOTOCORD
from what structure does most of the CNS arise
neural tube
from what structure does most of the PNS arise
neural crest
where does the spinal cord develop
caudal to the fourth pair of somites
what is spina bifida
failure of one or more neural folds to fuse
what is it called when there is an unfused neural arch but skin remains intact
spina bifida occulta
what is the difference btwn meningocele and meningomyelocele
in BOTH, meninges protrude through unfused arch
in meningomyelocele ONLY, neural tissue also protrudes
what is myeloschisis?
when neural tissue is open to external environment
what are the three primary vesicles
forebrain
midbrain
hindbrain
what are the five secondary vesicles
telencephalon diencephalon mesencephalon metencephalon myelencephalon
what secondary vesicles does the forebrain become
telencephalon
diencephalon
what secondary vesicles does the midbrain become
does not divide - remains midbrain AKA mesencephaln
what secondary vesicles does the hindbrain become
metencephalon
myelencephalon
what structures does the telencephalon develop into
wall: cerebral hemispheres
cavity: lateral ventricles
what structures does the diencephalon develop into
wall: thalamus (hypo, epi, para)
cavity: 3rd ventricle
what structures does the mesencephalon develop into
wall: midbrain
cavity: aqueduct
what structures does the metencephalon develop into
wall: pons and cerebellum
cavity: upper fourth ventricle
what structures does the myelencephalon develop into
wall: medulla
cavity: lower fourth ventricle
when does the brain bend?
week 5
what are the three flexures, from superior to inferior?
midbrain/mesencephalic
pontine
cervical
which flexure separates the medbrain from the forebrain
cephalic flexure
which flexure separates the spinal column from the hindbrain
cervical flexure
which flexure separates the myelencephalon and metencephalon
pontine flexure
in what secondary structure does migration of alar plate neuroblasts occur
myelencephalon
what do the alar plates give rise to
sensory nuclei
what do the basal plates give rise to
motor nuclei
from what structure of the metencephalon does the cerebellum arise
cerebellar swellings of the dorsal alar plate
what structure is overgrown in the development of the cerebellum
the 4th ventricle
what embryonic structure gives rise to the choroid plexus
tela chordea
where does the thalamus develop
on each side of the third ventricle
usually fuses at midline
from what structure does the pineal gland develop
from the caudal part of the roof of the diencephalon
when do optic vesicles appear
as the rostral neuropore is closing
where does the choroid plexus develop
from the tela chordiae at medial wall of the cerebral hemisphere
mesenchyme trapped in the fissure between the cerebral hemispheres as they expand becomes what?
falx cerebri
