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CNS Development
Neuroanatomy CNS Development
62
Anatomy
Graduate
03/14/2012

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Cards

Term
how do embryos begin
Definition
as a flat sheet of mesenchymal cells
Term
what does the embryonic sheet of mesenchymal cells doe
Definition
forms a hole in the middle of the sheet and the cells invaginate into the hol
Term
what is gastrulation
Definition
the invagination of mesenchymal cells into the hole
Term
what 3 primary germ layers are formed by gastrulation
Definition
ectoderm, mesoderm, endoderm
Term
what is the key consequence of gastrulation
Definition
formation of a notochord
Term
what is a notochorrd
Definition
cylinder of mesodermal cells that extends from anterior-posterior in the midline of the embryo
Term
what is the neuroectoderm
Definition
the ectoderm directly above the notochord
Term
what will the neuroectoderm become
Definition
entire nervous system
Term
what does the notochord do
Definition
sends inductive/instructive molecular signals to neuroectoderm cells, instructing them to become neural precursor cellss
Term
when does neurulation occur
Definition
after gastrulation
Term
what is neurulation
Definition
formation of the primitive nervous system
Term
what do the signalled neuroectoderm cells do in neurulation
Definition
thicken into the neural plate
Term
what is the neural plate
Definition
columnar epithelium formed by neuroectoderm cells
Term
how is the neural tube formed
Definition
lateral margins of the neural plate fold inward and upward
Term
what does the neural tube become
Definition
brain and spinal cord = entire CNS
Term
what forms somites
Definition
mesoderm adjacent to the neural tube
Term
what will somites become
Definition
axial muscles and skeleton/vertebrae
Term
where does the neural tube usually close
Definition
first at center then at both ends
Term
what do we call cells in the neural tube
Definition
neural precursor cells
Term
what do neural precursor cells become
Definition
first neuroblasts, then neurons
Term
what do neuroblasts become
Definition
neurons
Term
what is formed by ventral midline cells in the neural tube
Definition
floor plate
Term
what do cells in the floor plate do
Definition
tell other cells in the neural tube whether to become motor or sensory neurons
Term
what determines whether cells in the neural tube will become motor or sensory neurons
Definition
cells that are close to the floor plate are told to become motor neurons. Cells that are farther away don’t' get the memo and will become sensory neurons
Term
what is the basal plate
Definition
floor plate
Term
what is the alar plate
Definition
roof plate
Term
where are motor neurons formed
Definition
basal plate
Term
are motor neurons formed ventrally or dorsally
Definition
ventrally
Term
do motor neurons come out of the spinal cord at the ventral or dorsal horn
Definition
ventral
Term
what are the most dorsal cells of the neural tube
Definition
neural crest cells
Term
what is the sulcus limitans
Definition
limit of wher eneurons will be motor or sensory neurons
Term
in the brainstem, are motor nuclei medial or lateral
Definition
medial
Term
in the brainstem, are sensory nuclei medial or lateral
Definition
lateral
Term
what do neural crest cells do after they are formed
Definition
migrate away from the neural tube along specific pathways, which influences their final destination/fate
Term
what 5 things can neural crest cells eventually become, based on their final destination
Definition
1. sensory neurons in the dorsal root ganglia; 2. postganglionic autonomic nerves; 3. chromaffin cells of the adrenal gland; 4. non-neural cells (melanocytes, cartilage, bone cells); 5. schwann cells in the PNS
Term
if I'm a neuron in the basal plate, what am i
Definition
motor neuron
Term
if I'm a neuron in the alar plate, what am i
Definition
sensory neuron
Term
what is the result of failure of the posterior neural tube to close completely
Definition
spina bifida
Term
what is the result of failure of the anterior neural tube to close completely
Definition
anencephaly
Term
what is anencephaly
Definition
no brain
Term
what are 2 potential causes for neural tube abnormalities
Definition
retionic acid excess, folic acid insufficiency
Term
what can retinoic acid excess do
Definition
inhibit neural tube closure
Term
what can folic acid insufficiency do
Definition
alter proper neural tube formation by disputing cell division and motility
Term
what does retinoic acid come from
Definition
vitamin A
Term
what is spina bifida occulta
Definition
defect in vertebrae that doesn't affect neural tissue
Term
what is spina bifida cystica
Definition
neural tissue and/or meninges protrude through the defect in the vertebrae
Term
what is meningocele
Definition
meninges protrude through defect in vertebrae. Can be fixed surgically
Term
what is meningomyelocele
Definition
nerves entering spinal cord don't form properly. Lower limb paralysis and bladder/bowel problems
Term
what forms at the anterior bend of the neural tube
Definition
cephalic flexure
Term
what does the balloon at the very anterior end of the neural tube form
Definition
forebrain
Term
what is another term for forebrain
Definition
prosencephalon
Term
what forms in the cephlic flexure
Definition
midbrain
Term
what is another term for midbrain
Definition
mesencephalon
Term
what forms behind the cephalic flexure
Definition
hindbrain
Term
what is another term for hindbrain
Definition
rhombencephalon
Term
what bend is located behind the hindbrain
Definition
cervical flexure
Term
what forms the ventricals
Definition
the inside of the tube
Term
what does the prosencephalon divide into
Definition
telencephalon and diencephalon
Term
what does the rhombencephalon divide into
Definition
metencephalon and mylencephalon
Term
what does the metencephalon become
Definition
pons and cerebellum
Term
what does the mylencephalon become
Definition
medulla
Term
what is significant about the growth of the telencephalon
Definition
grows and curls around in a C-shape
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