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CNS arises from
ectoderm
Ntochord turns into
vertebral body
Neural tube turns into
CNS
The neural crest turns into
PNS
Neuroplate develops containing a neural groove and neural folds occurs by
18 days
The ends of the tube close and the walls become thickened to develop the brain and spinal cord occurs by
24-26 days
The hole down the center because the
ventricular system of the brain and the central canal of the SC
Somites
mesoderm (myotomes, sclerotome, and dermatome)
At ______ weeks the baby look human and has completed the most critical period of the CNS development
8 weeks
What week do neural folds fuse to form 3 pirmary brain vesicles
4th weeks
What week does the primary vesicles divide into 5 secondary vesicles
5th week
CNS proliferates and differentiates and fold upon each other to form the
cortical lobes and brainstem
What are the 3 primary vesicles
forebrain, midbrain, hindbrain
forebrain turns into
telencephalon and diencephalaon
Midbrain turns into
mesencephalon
Hinbrain turns into
Metencephalon
myelencephalon
telecephalon turns into
cerebral hemispheres
diencephalon turns into
thalmus
Mesencephalon turns into
midbrain
Metencephalon turns into
pons nd cerebelluma
The myelencephalon turns into
medulla oblongata
When are the major structures of the brain are present
24 weeks
What is the problem at 24 weeks?
The cardiopulm system and the immature brain, fetal brain is highly susceptible to anoxia which can occur from relative mild stresses to the brain
Hypoxemia
decrease O2 to the brain
Ischemia
decrease perfusion to brain
asphyxia is
lack of O2 without pulse (decrease in BP in children)
ability of the nervous to change is
plasticity
Critical peroid
activiy dependent chagnes in neural circuitry usually occue during a restricted time in development, the brain is particularly sensitive to the effect of experience
3-4 weeks what is the baby at risk for
myelo (spina bifida)
5-6 weeks baby is at risk for
agenesis of corpus callosum
9-16 weeks baby is at risk for
microcephaly
16-20 weeks baby is at risk for
skiz encephaly
vertebral column and udra matter grow more rapidly
than the spinal cord, so this relationship cahgnes
SC ends 8 weeks gestation
caudal end lies at tip of sacruj
SC ends 6 months gestation
caudal end lies at S1
Newborn SC ends
L3
adult SC ends
L1
Myslinization starts after neuron formation around
12-20 weeks gestation
What is first thing to be myelinized
medulla and cranial nerves for swallowing and sucking
Vestibular system is myelinated
by the end of the 5th month
fetal movements begin in utero at about
6-7 weeks gestation
felex movements in reponse to touch have been reposrted at early at
7-8 weeks
the first two months after birth are considered a peroid of
CNS organization
Critical peroids of brain growth
3-10 months, 15-24 months, synaptic proliferation from birth to 4 years
Positive babinski sign occurs
for first 6 mongths
