early development of the nervous system

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early development of the nervous
system neurulation malformations of neural tube
closure neural crest cells and the PNS initial
differentiation of the neural tube organization
of the spinal cord early divisions of the cranial
neural tube development of the brainstem developme
nt of the forebrain terminology regarding
orientation of the CNS
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neural plate
neuroepithelial cells neuroectoderm
surface ectoderm
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surface ectoderm
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neurulation
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closes on day 24
closes on day 26
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early development of the nervous
system neurulation malformations of neural tube
closure neural crest cells and the PNS initial
differentiation of the neural tube organization
of the spinal cord early divisions of the cranial
neural tube development of the brainstem developme
nt of the forebrain terminology regarding
orientation of the CNS
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closes on day 24
closes on day 26
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If the neural tube fails to fuse and separate
from the surface ectoderm, and therefore,
develops abnormally, then craniorachischisis
totalis- the entire neural tube fails to close
properly exencephaly, anencephaly,
craniorachischisis - incomplete development of
the cranial neural tube, resulting in a brain
that is an undifferentiated and exposed
mass rachischisis, myeloschisis - spinal cord
region fails to develop inionschisis -failure of
the neural tube near the occipital region to fuse
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exencephaly, anencephaly, craniorachischisis -
incomplete development of the cranial neural
tube, resulting in a brain that is an
undifferentiated and exposed mass
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inionschisis -failure of the neural tube to fuse
near the occipital region
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neural tube
vertebra
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spinal dysraphism - failure of neural tube to
close, usually at the cranial or caudal
neuropore spina bifida - failure of the vertebral
arches to fuse due to spinal dysraphism cele -
membranous sac protruding at the point of the
defect, usually components of the meninges, but
continuous with the skin
hydrocephaly - increased volume and pressure in
the cerebral ventricles due to interruption of
proper flow of cerebral spinal fluid
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If the neural tube develops normally, but its
failure to close in a timely fashion results in
failure of the vertebral arches to fuse, then
spinal bifida occulta- single vertebral arch
fails to fuse meningocele - protrusion of the
meninges through the defect meningomyelocele -
neural tissue and meninges protrude this is what
clinicians call spina bifida
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spinal bifida occulta- single vertebral arch
fails to fuse meningocele - protrusion of the
meninges through the defect meningomyelocele -
neural tissue and meninges protrude
Note that, even thought the neural tube fails to
close in a timely fashion, it may develop
normally. Here we have an apparently normal
CNS development, but a defect of the vertebral
arches. The vertebral defect may affect proper
CNS function
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meningomyelocele (a.k.a. spina bifida) - neural
tissue and meninges protrude
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folic acid and neural tube defects
valproic acid, etc. and neural tube defects
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem development of
the forebrain terminology regarding orientation
of the CNS
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neural crest formation
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Hirschsprungs disease
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem development of
the forebrain terminology regarding orientation
of the CNS
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neural tube initially pseudostratified epithelium
(single layer of cells)
cells proliferate, making neural tube stratified
(multiple layers of cells) so, neural tube gets
thicker, neural canal gets narrower
appearance of cell types neuroblasts glioblasts
ependymal cells
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem development of
the forebrain terminology regarding orientation
of the CNS
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Basal plate can be divided into --ventral
somatic motor neurons --dorsal autonomic
(preganglionic) motor neurons
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Some of these neurons also have collateral
branches --DRG neurons also project to
brainstem DCML --alar plate neurons have
numerous collateral projections
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem development of
the forebrain terminology regarding orientation
of the CNS
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orientation is opposite of pink cartoons
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pontine flexure
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem expansion of
the walls of the rhombencephalon organization of
brainstem cranial nerve nuclei development of the
forebrain terminology regarding orientation of
the CNS
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remember rhombencephalon is the medulla and pons
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remember rhombencephalon is the medulla and pons
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Note that central canal is much smaller in fully
developed spinal cord, caudal medulla, rostral
pons and midbrain
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apertures form connecting ventricular system with
subarachnoid space
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Note that central canal is much smaller in fully
developed spinal cord, caudal medulla, rostral
pons and midbrain
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem expansion of
the walls of the rhombencephalon organization of
brainstem cranial nerve nuclei development of the
forebrain terminology regarding orientation of
the CNS
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rostral medulla/ caudal pons
spinal cord
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ROSTRAL MEDULLA
SA special afferent GSA general somatic
afferent GVA general visceral afferent
GSE general somatic efferent BE branchial
efferent GVE general visceral efferent
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CAUDAL PONS
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midbrain
alar plate does not form cranial nerve sensory
nuclei here, but, like pons and medulla, forms
other association nuclei
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem development of
the forebrain development of the
diencephalon development of the
telencephalon terminology regarding orientation
of the CNS
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choroid plexus forms here
thin because of expanding thalami
all from alar plate
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem development of
the forebrain development of the
diencephalon development of the
telencephalon terminology regarding orientation
of the CNS
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cerebral cortex
corpus striatum
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falx cerebri
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early development of the nervous system neural
crest cells and the PNS initial differentiation
of the neural tube organization of the spinal
cord early divisions of the cranial neural
tube development of the brainstem development of
the forebrain terminology regarding orientation
of the CNS
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