Dev of Nervous System Flashcards
1
Q
when does the dev of nervous system start
A
3rd week of dev
2
Q
explain how the neural plate is formed
A
ectoderm at the dorsal surface of embryo bet primitive knot and buccopharyngeal membrane thickens forming neural plate
3
Q
describe the shape of neural plate
A
pear shaped and wider cranially
4
Q
explain how the neural fold is formed
A
plate will develop a longitudinal neural groove that will deepen and as it deepens lateral edges elevate forming neural folds
5
Q
explain how the neural tube is formed
A
neural folds will fuse starting at cervical region and extends in cephalic and caudal direction to from the neural tube
6
Q
what are the open ends of the neural tube
A
anterior and posterior neuropores
7
Q
when does the neural tube close
A
28 days in general
cranial neuropore - 25th
caudal neuropore - 28th
8
Q
explain the difference from an open fold once that tube has closes
A
the tube sinks beneath the surface of the ectoderm
9
Q
it refers to the 3 dilations of the cephalic end of neural tube
A
primary brain vesicles
10
Q
what are the primary brain vesicles
A
prosencephalon
mesencephalon
rhombencephalon
11
Q
what are the 2 flexures of the rhombencephalon
A
cephalic - midbrain
cervical - bet hindbrain and SC
12
Q
what is the main thing happens at the 5th week of development
A
primary vesicles differentiate into 5 secondary vesicles
13
Q
the ______ is continuous w the brain vesicles
A
central canal of SC
14
Q
prosencephalon differentiates into what
A
telencephalon
diencephalon
15
Q
mesencephalon differentiates into what
A
mesencephalon
16
Q
rhombencephalon differentiates into what
A
metencephalon
myelencephalon
17
Q
what separates mesencephalon and metencephalon
A
rhombencephalic isthmus
18
Q
what separates metencephalon and myelenecephalon
A
pontine flexure
19
Q
corresponding cavity/lumen of telencephalon
A
lateral vent
20
Q
corresponding cavity/lumen of diencephalon
A
3rd vent
21
Q
corresponding cavity/lumen of mesencephalon
A
cerebral aqeuduct of sylvius
22
Q
corresponding cavity/lumen of metencephalon and myelencephalon
A
4th vent
23
Q
discuss the formation of floor and roof plates of the SC
A
cavity of neural tube narrows to form a dorsiventral cleft with lateral walls and thin floor and roof plates
24
Q
how are basal and alar plates formed in general
A
intermediate zone of the lateral wall forms large anterior thickening basal plate and small posterior thickening alar plate
25
compare basal and alar plate
basal - ventral, larger, motor
alar - dorsal, smaller, sensory
26
refers to the longitudinal groove bet dorsal and ventral horn cells
sulcus limitans
27
forms due to the continuous growth of basal plate
anterior median fissure
28
forms due to the continuous growth of alar plate
posterior median septun
29
what forms the central canal of the SC
narrowing of the lumen of the neural tube
30
how are intermediate zones of the SC formed
bc neuroblast cannot divide further they migrate peripherally to form intermediate zone
31
how are marginal zones of the SC formed
neuroblasts will also grow peripherally forming a layer external to the intermediate zone known as the marginal zone
32
what is the significance of intermediate and marginal zone in SC
intermediate - becomes gray matter of SC
marginal - becomes myelinated; white matter of SC
33
what do matrix cells give rise to
astrocytes, oligodendrocytes and ependymal cells
34
where do matrix cells come from
the wall of neural tube contains pseudostratified columnar epithelial cells
35
what happens to the neural tube as the development progresses
it elongates and remain small in diameter
36
what is the ventricular zone
zone directly after the cavity of neural tube composes of the neuroepithelial later
37
explain the connection of cell division and the neural tube
nuclei of cells move in towards the cavity to divide and outward to the periphery during intermitotic phases
38
what happens to cells once the neural tube closes
neuroepithelial cells give rise to neuroblasts
39
discuss the development of motor neuron
medial group - axons leave anterior surface of SC to supply muscles
lateral group - axons that leaves as autonomic preganglionic fibers
together they form the anterior root of SC
40
compare medial and lateral group of motor neurons
medial - motor cla sa mga muscles
lateral - supplies for ANS
41
what SC roots are autonomic preganglionic fibers
T1-L3
41
discuss the development of afferent neurons in sensory pathway
neural crest cells migrate to the posterolateral pos on both side of SC and differentiates into neuroblasts
42
what happens to central processes of afferent sensory neurons
becomes posterior root of SC
42
what are the 2 processes neuroblasts develop into
peripheral - axons of sensory nerve fibers
central - migrates to posterior part of SC and mapupunta either posterior gray column or sa marginal zone na white
42
how are posterior root ganglion formed
neural crest cells form the capsular/satellite cells that surround a unipolar nerve cell body
43
how are meninges in VC formed
from mesenchyme and ssurround nila neural tube
44
what is the length of VC and SC at 2 mo of development
same length but VC grows more so VC > SC
45
what is the significance of a longer VC than SC
ant and post roots of SN below L1 descend within the VC until they reach their IV foramen exits
46
what is filum terminale
pia matter that is attached to the coccygeal end of SC until coccyx; slender fibrous strand
47
what is cauda equina
horse tail
passes obliquely sa anterior and posterior roots of SN and filum terminale found at the lower end of VC
48
which secondary vesicle does the medulla oblongata come from
myelencephalon
49
discuss the initial formation of the medulla
initially may basal and alar plates separated by a sulcus limitans
the lateral walls will move laterally at higher levels expanding the 4th ventricle
50
in the formation of the medulla the basal and alar plates are separated by _______
sulcus limitans
51
in the formation of the medulla the lateral walls move laterally expanding the _______
4th ventricle
52
alar plates lie _____ to basal plates
lateral
53
neurons of basal plate of the medulla form motor nuclei of which cranial nerves
CN IX, X, XI AND XII
54
the motor nuclei from the basal plate are situated where in the cerebellum
floor of 4th ventricle medial to the sulcus limitans
55
neurons of alar plate from the medulla form which sensory nuclei of which cranial nerves/structures
CN V, VIII, IX and X
gracile and cuneate nuclei
56
how is the olivary nuclei of the medulla formed
others of alar plate migrate ventrolat and forms it
57
what are the nuclei formed from the medulla
basal - CN IX, X, XI AND XII
alar - CN V, VIII, IX and X anf gracile and cuneate nuclei
olivary nuclei
58
in the stretching of the lateral walls in forming the medulla what is its effect on the roof plate
it is stretched into a thin layer
59
in the medulla the vascular mesenchyme comes in contact with the roof plate and forms _______
pia matter; together called telachoriodea
60
vasculat tufts of tele choroidea project in the cavity of the 4th vent to form the _______
choroid plexus
61
_______ of tele choroidea project in the cavity of the 4th vent
vascula tufts
62
discuss what happens in the medulla between 4th and 5th months
2 lateral foramen of luschka and 1 medial foramen of magendie forms allowing connection of ventricles to subarachnoid space
63
the basal plate of the pons forms which motor nuclei
CN V, VI, VII
64
the ventromedial aspect of each alar plate of the pons form what
sensory nucleus of CN V, VII
vestibular
cochlear nuclei of CN VIII
pontine nuclei
64
axons of the pontine nuclei grow ________ (direction) and enters ______
transversely
developing cerebellum of opposite side
65
what does the entering pontine nuclei axons entering the cerebellum form
transverse pontine fiber and the middle cerebellar peduncle
66
the pons came from which secondary brain vesicle
ventral part of metencephalon
67
the cerebellum came from which secondary brain vesicle
posterior part of metencephalon
68
discuss how the formation of the cerebellum starts
alar plated bend medially forming rhombic lips
as as the alar plate enlarges the lips project caudally over the 4th vent and unite with each other at midline to form the cerebellum
69
discuss the dev of cerebellum at 12th week
vermis and cerebellar hemispheres are recognized
70
discuss the dev of cerebellum at end of 4th month
fissures develop on the surface now creating folia
71
how is the cerebellar cortex formed
neuroblasts from the matrix cells in the ventricular zone migrate to the surface forming the cortex
72
how is cerebellar nuclei formed
other neuroblasts will not migrate and they differentiate into cerebellar nuclei
73
what is superior cerebellar peduncle
axons of these neurons grow into the mesencephalon reaching the forebrain
74
what is middle cerebellar peduncle
axons of pontocerebellar and corticopontine fibers connect the cerebral cortex w the cerebellum
75
Hos is inferior cerebellar peduncle formed
from growth of sensory axons from SC and vestibular and olivary nuclei
76
what does the basal plate of the midbrain form
nuclei CN III and IV, red nuclei, subtantia nigra and reticular formation
77
what does the marginal zone basal plate of the midbrain form
basis pedunculi by the descent of fibers from the cerebral cortex to the pons and SC
78
what are the fibers that descend to form the basis pedunculi
corticopontine, cortiobulbar and corticospinal
79
what does the alar and floor plates of the midbrain form
superior and inferior colliculi
80
corresponding sense from superior colliculi
visual reflex
81
corresponding sense from inferior colliculi
auditory reflexes
82
discuss the path of CN IV fibers in the midbrain
emerge in the posterior surface of midbrain and decussate in the superior medullary velum
83
what brain vesicle is the forebrain from
prosencephalon
84
discuss the formation of the forebrain
floor and roof plate remain thin while lateral walls become thick tas mag kakaron ng lateral diverticulum
85
what is the lateral diverticulum in the forebrain called
optic vesicle
86
discuss the significance of the optic vesicle
rostral to it is the telencephalon and caudal to is the the diencephalon
87
from the optic vesicle what forms out of it
retina and optic nerve
88
what is present in the roof of diencephalon fate and what will it form
small diverticulum anterior to midbrain and it will become the pineal body
89
after forming the pineal body the rest of the roof of the DF will form the ______
choroid plexus of the 3rd vent
90
what arises in the lateral wall of the 3rd vent
thalamus from the thickening of the alar plate
91
in the DF what develops posterior to the thalamus
medial and lateral geniculate bodies
92
what occurs due to the continues growth of the thalamus
3rd vent narrows
93
define interthalamic connection in the DF
it refers to the fusion of 2 thalami through the 3rd vent
94
what will the lower part of the alar plate become to in the DF
hypothalamic nuclei and mamillary bodies
95
how is the infundibulum formed in the DF
comes from a diverticulum from the floor of the diencephalon
96
what originates from the infundibulum
stalk and the pars nervosa of pituitary gland (hypophyis)
97
what does telencephalon form
anterior end of 3rd vent
98
what closes the anterior end of 3rd vent
lamina terminalis
99
the diverticulum on either side of TF forms the _________
cerebral hemisphere
100
which stage of development does cerebral hemispheres rise
5th week of dev
101
relate the cerebral hemisphere and the intervent foramen
as cerebral hemispheres expand superiorly its walls thickens and intervent foramen reduces in size
102
the mesenchyme bet each cerebral hemi forms _______
condenses to form the falx cerebri
103
what does the CH form ant
frontal lobe
104
what does the CH form lat and sup
parietal
105
what does the CH form post and inf
occipital and temporal
106
describe the medial wall of the CH
remains thin and formed by epednymal cells
107
what occurs at the medial wall of the CH
invaginated by vascular mesoderm which forms the choroid plexus of lat vent
108
whaat separates the occipital lobe from the cerebellum
mesenchyme
109
what does the mesenchyme at OL form
condenses to from tentorium cerebelli
110
______ line the floor of the forebrain vesicle and proliferate producing ______
matrix cells; neuroblast
111
what is the significance of neuroblasts in the floor of forebrain vesicle
they form a projection that encroaches the cavity of the lat vent
112
refers to the projection that encroaches the cavity of the lat vent
corpus striatum
113
what forms from the dorsomedial portion of the corpus striatum
caudate nucleus
114
what forms from the ventrolateral portion of the corpus striatum
lentiform nucleus
115
name the lateral and the medial part of the lentiform nucleus
lat - putamen
med - globus pallidus
116
explain why the caudate nuc and the thalamus are close in contact
each CH expands and its medial surface approaches the lat surface of diencephalon kaya caudate nuc is close sa thalamus
117
discuss the longitudinal thickening in the CH and what does it form
it occurs walls of forebrain vesicle and protrudes into the lateral ventricle
hippocampus
118
discuss the asc and desc tracts in the CH nd what does it form
it forms and are forced to pass betw thalamus and caudate med and lentiform laterally
internal capsule
119
what happens at the cortex as the CH expand more
the gyri and sulci/fissures become more evident mga convolutions
120
how is the insula formed
cortex covering the lentiform remains fixed tas will get buried by overgrowth of the frontal, parietal and temporal lobes
121
discuss what happens to the matrix cells lining the cavity of CH
will produce many neurobalsts and neuroglia that migrate to marginal zone
122
what happens to the matrix cells that wont migrate to the marginal zone of CC
form the ependyma that lines the lat vent
123
describe the cortex at 12th week
it is very cerebellar due to migration of neuroblasts
124
describe the cortex at term
neuroblasts have differentiated and assumed stratified appearance due to result of incoming and outgoing fibers
125
type of cells in motor cortex
pyramidal
126
type of cells in sensory cortex
granular cells
127
it refers to the cephalic end of the nueral tube
lamina terminalis
128
what does the lamina terminalis become
septum pellucidum
129
it is the first commisure to develop
anterior commisure
130
where does the AC run and what does it connect
runs in lamina terminalis and connects the olfactory bulb and the temporal lobe on one side and to the same structures sa kabila
131
what connects the hippocampus in each hemisphere
fornix
132
what connects the CH
corpus callosum
133
largest and most important commisure
corpus callosum
134
formed in the inferior part of the lamina terminalis
optic chiasm
135
what forms the myelination in the CNS
oligodendrocytes
136
when does myelination begin at SC
4th month
137
discuss the manner of myelination in the SC
cervical and extends caudally
sensory muna last and descending motor fibers
138
when does myelination begin at brain
6th month pero fibers from the basal ganglia pa lang
139
discuss the manner of myelination in the brain intrauterine
6th month basal ganglia fibers - sensory fibers coming from SC but slow
140
discuss the manner of myelination in the brain at birth
largely myelinated
corticobulbar, corticospinal, tectospinal and corticopontocerebellar fibers begin to myelinate
141
is myelination complete at birth ?
not until puberty
142
what forms myelination outside of CNS
schwann cells
143
