Brain During Development Flashcards
what are the last portions of the neural tube to close called
anterior and posterior neuropores
when do the last portions of the neural tube close
end of the embryonic week
what does the neural tube surround
fluid filled central cavity
rostral end of the neural tube
larger and more irregular
gives rise to the brain
closure of caudal neruopore
corresponds to the upper lumbar segments of the cord
how does the brain develop
3 major brain divisions –> occur @ 3/4 week
secondary divisions –> @ 5th week
3 major brain divisions during development
prosencephalon (forebrain)
mesencephalon (midbrain)
rhombencephalon (hindbrain)
secondary divisions –> prosencephalon
telencephalon
diencephalon
secondary divisions –> rhombencephalon
metencephalon
myelencephalon
rhombencephalon –> myelencephalon –> mature brain?
medulla oblangata
rhombencephalon –> metencephalon –> mature brain?
pons and cerebellum
mesencephalon –> mature brain?
midbrain
prosencephalon –> diencephalon –> mature brain?
thalamus
epithalamus
hypothalamus
subthalamus
prosencephalon –> telencephalon–> mature brain?
cerebral hemispheres
corpus striatum
cerebral cortex
white matter
slide 60
pic
what do flexures do
accommodate the shape changes of the brain as it becomes round
different flexures
cervical
mesencephalic
pontine
cervical flexure
jxn of the rhombencephalon w/ the spinal cord
mesencephalic flexure
level of the midbrain
pontine flexure
in the metencephalon
when do meninges first appear
4th week as single mesodermally derived primary meninx
when do fluid-filled spaces appear
w/in the primary meninx
1 week later
giving rise to meninges
layers of the meninges from inside out
pia mater –> arachnoid –> dura mater
pia mater
closest to nervous tissue
arachnoid
interposed b/w the pia and dura mater
spiderweb-like
dura mater
lines the cranial cavity and the spinal canal
what will permeate the CSF
ventricle lateral
how does the ventricle lateral develop
neural tube will undergo changes and finally expend to form ventricle lateral
CSF is produced by
plexus coroid
underlies certain part of the ventricle lateral wall
how will CSF flow
through the ventricle system, spinal corda centre system and subarachnoid channel
Holoprosencephaly (HPE)
congenital anomaly
incomplete development of the brain
how much does the brain weigh at birth
400 g
when is the most rapid growth of the brain
in utero
during 1st 20 prenatal weeks
by age 3 the weight of the brain is
1200g
almost the weight of an adult brain
slow growth till age 18
after age 50 the brain
slowly declines in brain size
does size of the brain indicate intelligence
no
when gender has a larger brain
male
CNS is formed by
neural tube
PNS is formed by
nueral crest
what are the first cells to differentiate in the nervous system
neuros
communicating cells
2nd cells to differentiate in the NS
neuroglia
supporting cells
when are major divisions of the CNS present
4th week after fertilization
when does the cerebellum appear
later
outgrowth of the brainstem (appears in 4th week of fertilization)
