CNS Dev't Flashcards
(114 cards)
0
Q
neurulation occurs until
A
Day 28
1
Q
entire process of neural fold formation, elevation, and closure
A
neurulation
2
Q
appearance of notocord and precordial mesoderm induces overlying ectoderm to thicken forming
A
neural plate
3
Q
How is neural fold formed
A
lateral edges of the neural plate begins to elevate
4
Q
depressed region in the midline of neural plate
A
Neural grove
5
Q
neural folds fused midline
A
neural tube
6
Q
neural tube opens posteriorly and anteriorly called
A
neuropores
7
Q
closes by day 25
A
anterior (cranial) neuropore
8
Q
closes by day 28
A
posterior (caudal) neuropore
9
Q
Complete neurulation
A
closure of posterior neuropore
10
Q
CNS with T-shaped form is having an
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Elongated caudal end
Broader cranial end
11
Q
3 vesical stage
A
Prosencephalon
Mesencephalon
Rhombencephalon
12
Q
Flexures present during 27 days
A
Cephalic
Cervical
13
Q
5 Vesical stage
A
prosencephalon : Telencephalon (lateral ventricle, cerebral hemisphere) & Diencephalon (3rd ventricle and thalamus, hypothalamus)
Mesencephalon: Aqueduct of Sylvius (tectum, crus cerebri)
Rhombencephalon :Metenceohalon ( upper 4th vent, pons& cerebellum) Mesencephalon (lower 4th vent, medulla)
14
Q
separates Mesencephalon and Rhombencephalon
A
Rhombocephalic isthmus
15
Q
Junction of the hindbrain and SC ; disappears at 4th month
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Cervical Flexure
16
Q
Flexure at midbrain region; disappears at 3 vesical stage
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Cephalic flexure
17
Q
between Metencephalon and Myelencephalon
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Pontine Flexure
18
Q
Cavity of cerebral hemispheres
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lateral ventricles
19
Q
Communicates the lateral ventricle with 3rd ventricle
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Interventricular foramina of. monroe
20
Q
cavity of diencephalon
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third ventricles
21
Q
lumen of mesencephalon ;connects 3rd and 4th ventricles
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aqueduct of sylvius
22
Q
Cavity of rhombencephalon
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4th ventricle
23
Q
lumen of Sc
A
central canal
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collection of neuroepithelial cells which extends the entire wall and forms
Pseudostratified epithelium
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further differentiation of neuroblasts and makes up the grey matter of SC having a large round nucleus and pale nucleoplasm
Mantle layer
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continous addition of neuroblasts to mantle layer results to
Ventral and Dorsal thickening
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Sensory area formed from dorsal thickening of the neural tube
Alar plate
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motor area formed by ventral thickening
Basal plate
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boundary of basal and alar plates
Sulcus Limitans
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midline of neural tube serves as pathway for nerve fibers
Roof and Floor plates
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small group of neurons accumulating between sensory and motor plates
intermediate horn
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outermost layer of SC that comproses the white matter and is myelinated
Marginal layer
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has transient dendrites that are lost when entering mantle later
neuroblast/ primitive nerve cells
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temporary round cell
Apolar neuroblast
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2 cytoplasmic processes on opposite cite of cell body
Bipolar neuroblasts
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Has primitive axon and primitive dendrites
multiplar neuroblasts
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axons in the basal plate penetrate the marginal layer and become visible on ventral aspect of cord
ventral motor root of spinal nerve
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axons in alar plate penetrate marginal layers and ascend or descend as
association neuron
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formed when neuroblast production ceases and migrate fr neuroepithelial layer to mantle and marginal
Glial blast
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glialblast in mantle and is seen b/w blood vessels
protoplasmic astrocytes and fibrillar astrocytes
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glialblast migrated to marginal layers and forms myelin sheath
Ologodendrial cells
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from vascular mesenchyme and is highly phagocytic
microglial cells
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when neuroepithelial cells ceases to produce neuroblasts, seen in central canal of SC
ependymal cells
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from cells that dissociate from the lateral border of the elevated fused neural fold during the elevation of neural plate and gives rise to sensory ganglia
neural crest cells
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penetrate dorsal portion of the neural tube in the dorsal horn ans ascend to marginal layers
Centrally growing ( dorsal sensory root)
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joins fibers of ventral motor roots to form trunk of spunal nerve
peripherally growing processes
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present during 4th mo of fetal life and myelinate perioheral nerves forming neurolemma or neural sheath derived from neural crest cells
schwann cells
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myelinate fibers in SC derived from glialblasts
Oligodendrial cells
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Changes in the 3rd month of devt
SC extend entire length of embryo
| Spinal nerves emerging fr respective intervertebral foramina at level of origin
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terminal end of the cord during birth
L2-L3
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terminal end of the cord during adult
L1-L2
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threadlike extension of Pia matter at end of SC; marks the regression of SC and supports the cord
filum terminale
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covered with dura extending from S2 to coccyx
coccygeal ligament
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nerve fibers below end of cord
cauda equina
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gives rise to medulla oblongata
Myelencephalon
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includes CN12 supplying tongue
Median somatic efferent of Basal plate of myelencephalon
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includes the CN 6,9,10 supplying striated m of pharyngeal arches
Intermediate special visceral efferent
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include the involuntary ms of respiratory tract, GIT and ❤️
lateral general visceral efferent of basal nuclei of myelencephalon
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recieves interoceptive info from GIT and ❤️
medial general visceral afferent of alar plate of mylencephalon
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recieves impulses fr taste buds, oropharynx, epiglottis, Cn8 for hearing and balance
intermediate special viscreal afferent of alar plate of myelencephalon
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recieves pain touch and sensory from pharynx and CN9
lat somatic visceral afferent of alar plate of myelencephalon
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vascular mesenchyme covering roof plate
pia matter
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pia matter + roof plate
tela choroidea
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tuft like invaginations that produce CSF
choroid plexus
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forms the cerebellum (pathway for posture) and pons (pathway for nerve fibers)
Metencephalon
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gives rise to nucleus of CN6
medial somatic afferent of basal plate of metencephalon
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contain nuclei of CN5&7
Intermediate special visceral efferent of basal plate of metencephalon
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supply submandibular and sublingual glands
lateral general visceral efferent of basal plate of metencephalon
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dorsolateral part of alar plates bending medially
Rhombic lips
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formed when potine flexure deepens and rhomben lips are compressed at 12th wk of devt
cerebellar plate
71
cerebellar plate contains:
```
Vermis ( small midline portion below ant and post colliculi)
Cerebellar Hemisphere (two lateral portions alongside vermis)
Flocculonodular lobe (primitive part of cerebellum)
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midbrain
mesencephalon
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represented by CN3&4 innervationg eye muscles
Medial somatic efferent of basal plate of mesencephalon
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bby nucleus of Edinger-Westphal innervating sphincter pupillary muscle
General Visceral efferent of basal plate of mesencephalon
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pathway for nerve fibers from cerebral cortex to lower center in pons and SC
Crus cerebri
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part of alar plate of mesencephalon that fxn as correlatuon and reflex center for visual impulses
ant (sup) colliculus
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synaptic relay for auditory reflexes
post(inferior) colliculi
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develop fr median portion of prosencephalon and 1 roof plate and 2 alar plate and no floor or basal plate
Diencephalon
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most caudal part of roof plate appearing as ep thickening which channels through light and dark affect behavioral rhythms
Pineal body or epiphysis
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dorsal region of alar plate
thalamus
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fusion of right and left thalamic regions
massa intermedia or interthalamic connexus
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ventral region of alar plate which diff into nuclear areas that regulates visceral fxns including sleep
hypotahlamus
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distinct protuberance on ventral surface of hypothalamus
mamillary body
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from ectodermal outpcketing and floor of dienceohalon
piyuitary gland
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most rostral or anterior of brain vescicles
Telencephalon
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consist of 2 lat cerebral hemispheres and median lamina
telencephalon
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lateral ventricles communiacte with lumen of diencephalon via
interventricular foramina of Monro
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arise at the beggining of 5thweek of devt
cerebral hemispheres
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repidly growing region with striations
corpus striatum
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two divisions of corpus striatum
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Lentiform nucleus (ventrolateral portion)
Caudate nucleus (dorsolateral portion)
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forms at roof of hemisphere but protrudes to lateral ventricle
Choroid plexus
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above the choroidal fissure bulges into kateral ventricles and fxns in olfaction
Hippocampus
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Cerebral hemispheres grow into:
Anterior (frontal lobe)
Dorsal (temporal lobe)
Inferior(occipital lobe)
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depressed area b/w frontal and temporal lobe
Insular lobes
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originates from pallium
Cerebral cortex
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regions of cerebral cortex
palleopalium (immediately lateral to corpus striatum)
| neopallium(in b/w palleopaliumun and hippocampus)
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fiber bundles lining midline connecting L and R halves of hemisphere
commisure
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appears on 19th week and connects non olfactory area of R and L cerebral cortices
Corpus Callosum
99
results to continous expansion of neopallium
corpus callosum
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fibers connecting olfactory bulb and related brain areas to one hemisphere of opposite side
anterion commisure
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arise in hippocampus converging to lamina terminalis
hippocampal or fornix comissiure
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below the stalk of pineal gland
habenular commisure
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aooear on rostral wall of diencephalom
optic chiasm
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incomplete development of ventral arches
spina Bifida
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what prevents spina bifida
folic acid
106
defectin vertebral arches still covered by skin and does not involve underlying neural tissue
Spina bifida occulta
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Severe NTD defect in neural tissues
Spina bifida cystica
108
NT defect in which only fluid filled meninges bulge through; affected occipital bone is smal
meningoceole
109
another ossification defect wherein meninges and part of the brain are herniated throughout the skull
meningomyelocoele
110
failure of the neural tube to close the remaining as flattened mass or neural tissue. exposes neural tissues making it susceptible to infection
rachishisis
111
spectrum of abnormalities due to loss of midline structures resulting to malformations of brain and face ; frontal loves and basal ganglia fused
Holoprosencephaly
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large clefts extending from cortex to ventricle sometimes causing loss of brain tissue; mutation in homeobox EMX2
Schizencephaly ( open or closed )
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NTD characterized by sac like protussions of brain and membranes covering it. Caused by failure of neural tube to close. classified to meningocoele, encephalocoele, naso orbital, naso ethmoidal, and overlapping of such
encephalocoele
