Neuroembryology Flashcards
1
Q
Major milestones
A
Gastrulation
Neural Induction and Neurulation
Neurogenesis/Neuronal Proliferation
Cell Migration
Development of Axons and Dendrites
Synaptogenesis and Pruning
Myelination
Formation of Neural Circuitries
2
Q
Nervous system develops between _ and _
A
4 weeks and adulthood
3
Q
Brain weight at birth
A
800 g
4
Q
Brain weight at 6 y/o
A
1200 g
5
Q
Brain weight at adult
A
1400 g
6
Q
_% of birth associated with major malformation of the CNS
A
3
7
Q
_% spontaneous aborted fetus
A
75
8
Q
_% of infants who die within the 1st yr of life have major CNS malformations
A
40
9
Q
Conceptus wk
A
1-2
10
Q
Embryonic development wk
A
3-8
11
Q
Fetal period wk
A
9-38
12
Q
Loss happens on
A
Conceptus
13
Q
Major abnormalities happen on
A
Embryonic development
14
Q
Functional and Minor abnormalities happen on
A
Fetal period
15
Q
Early developmental process in which an embryo transforms from 1 dimensional layer of epithelial cells (blastula) and reorganizes into a multilayered and multidimensional (glastula)
A
Grastulation
16
Q
Formation of trilaminar from bilaminar disc
A
Gastrulation
17
Q
Gastrulation happens on wk
A
3
18
Q
Gastrulation give rise to
A
Ectoderm
Mesoderm
Endoderm
Primitive node and streak
19
Q
Process before gastrula
A
Zygote
Blastomere
Morula
Blastocyst
Blastula
Gastrula
20
Q
Neural tissue appears at __wk
A
3rd
21
Q
Embryo is composed of 3 primary germ layers
A
Ectoderm
Endoderm
Mesoderm
22
Q
Ectoderm forms
A
CNS,skin
23
Q
Mesoderm forms
A
Connective tissue, muscles, vascular structures, bone marrow, portions of internal organ
24
Q
Endoderm forms
A
Lungs, liver, and gut
25
Establishes the basic body plan of all vertebrae
--midline axis, bilat sym, rostral and caudal ends, dorsal and ventral surfaces
Primitive streak
26
Defines the rostral direction
--as the node regresses, a notochordal process develops in the area rostral to it and somites begin to form on either side of the notochord
Primitive node/Hensen's node
27
Induces epiblast cells to form neuroectoderm
Notochord
28
A process of cell to cell signaling by which the underlying mesoderm induces the ectoderm to become neuroectoderm and form the neural plate, giving rise to most of the nervous system
Induction
29
Neural induction takes place in the
ectoderm of the head process overlying the notochord
30
Neural induction starts about the
16th to 17th day of intrauterine life
31
Neuroectodermal induction is d/t
Hormones, growth factors, neurotransmitters
32
Notochord came from
axial mesoderm, day 16 - beginning of 4thweek
33
Directs the overlying ectoderm to form the neural plate
Induction (noggin & chordin)
34
Notochord defines the longitudinal axis by
production of cell adhesion molecules
35
Determine the orientation of the vertebral column
Notochord
36
Persist as the nucleus pulposus of the intervertebral disk
Notochord
37
Neural plate is formed on
Day 18
38
Neural fold is formed on
Day 20
39
Slipper-shaped plate of thickened ectoderm
Neural plate
40
Located in the mid dorsal region in front of the primitive gut
neural plate
41
Lateral edges become elevated to form the neural folds
Neural plate
42
Neural folds become more elevated, approach each midline and fuse to form the
neural tube
43
Neural folds form on Day
20
44
Day 21 neural folds touching each other forms the
neural tube
45
Primitive streak emerges as a groove at the
caudal (lower part) pole of the embryo
46
Primitive node emerges in the
cranial pole (upper part)
47
Epiblast cells moving along the primitive streak and the nodes form the
3 germ layers
48
Thickening of the ectoderm forms the
Neural plate in the cranial pole
49
Primitive streak in the caudal part initiates the
Gastrulation
50
Somites are made up of
Mesodermal cells
51
Somites could be seen on
20th days
52
Somites give supports to
neural folds, which are the precursors of the vertebrae
53
Closure of the neural tube proceeds
bidirectionally
54
Fusion begins at the
center at the developing neural tube then proceed like a closing a double headed zipper
55
Unclosed cephalic portion & caudal part of the neural tube are called the
anterior and posterior neuropores
56
The lumen or the opening of the neural tube is open to the
Amniotic Cavity Rostrally and Caudally
57
The neuropores will close at __ days
24 Cranial; 26 Caudal
58
A process by which the neural plate folds over itself and fuses in a zipperlike fashion to become a neural tube
Neurulation
59
The process by which the brain and most of the spinal cord are formed
Primary neuralation
60
__ begins when the notochord induces the overlying embryonic ectoderm to form a neural plate (day __) and ends by Day __
Neurulation, Day 18, Day 28
61
The process by which the caudal parts of the spinal cord are formed
Secondary Neuralation
62
Duration of Secondary Neuralation
Day 20 - 42
63
Mass of cells that develop in the caudal part of the neural tube and it enlarges eventually becomes continuous with the neural tube
Caudal Eminence
64
Primary vs secondary neuralation
Initial epithelium
P
65
Primary vs secondary neuralation
Columnarization
P
66
Primary vs secondary neuralation
Rolling/folding
P
67
Primary vs secondary neuralation
Closure
P
68
Primary vs secondary neuralation
Dispersed Mesenchyme
S
69
Primary vs secondary neuralation
Mesenchymal condensation
S
70
Primary vs secondary neuralation
Medullary cord/neural rod
S
71
Primary vs secondary neuralation
Epithelial Transition
S
72
Ant neural pore failure to close
anencephaly 5:500000
73
Posterior neural pore failure to close
Spina bifida 1:1000
74
Defective primary neuralation aka
Dysraphic defects
75
Anterior neuropore Failure to close
Anencephaly
Encephalocoele/Cranial bifidum
Chiari I malformation
76
Posterior neuropore Failure to close
Spina bifida oculta
Spina bifida aperta
Spina bifida Cystica
77
Disorder of dorsal induction
Spinal Dyraphism
78
Minor fusion failure of posterior vertebral arches unaccompanied by herniation of meninges or neural tissue
Spina bifida occulta
79
Collectively designates meningocele, myelomeningocele, and other cystic lesion
Spina bifida cystica
80
Anencephaly __ times more in female than in male newborns
37
81
Anencephaly screening
sAFP
82
Prevention of anencephaly
folic acid
83
One month after the fertilization,in which the anterior pore closes, there is a rapid development of neural tissues in the cranial region, the three primary vesicle is formed
Prosencephalon, Mesencephalon, Rhombencephalon
84
Rhobencephalon and the spinal cord junction, __ flexure will be formed
Cervical
85
Second flexure at the level of mesencephalon
Mesencephalic flexure
86
Between the 4th and 8th weeks, the brain folds sharply at:
Mesencephalic, Pontine, Cervical flexures
87
During the __ week, further subdivisions of the brain vesicle creates 5 secondary vesicle
5th week
Prosencephalon - Telencephalon, Diencephalon
Mesencephalon - Mesencephalon
Rhombencephalon - Metencephalon, Myelencephalon
88
Forms as an outpocketing of the forebrain and expand enormously with its complex lobes, gyri, and sulci
Telencephalon
89
Telencephalon later on become
Cerebrum, basal ganglia, and diencephalon
90
Second month of gestation, mesoderm is forming
Facial structures
91
Process of forebrain development
Ventral Induction
92
Rhombencephalon is divide into
Metencephalon rostrally, Myelencephallon caudally
93
Diencephalon turn into
Thalamus, hypothalamus, Pineal body, Infundibulum, Optic Cup
94
Mesencephalon turn into
Tectum, tegmentum, crus cerebri
95
Metencephalon turn into
Pons, Cerebellum
96
Myelencephalon turn into
medulla oblongata
97
Cavity of Telencephalon
Lateral Ventricle
98
Cavity of diencephalon
Third Ventricle
99
Cavity of Midbrain
Cerebral Aqueduct
100
Cavity of Metencephalon
Upper 4th Ventricle
101
Cavity of Myelencephalon
Lower 4th Ventricle
102
The lumen of the neural tube persist as the
Ventricular system of the adult brain
102
Condition in Diencephalon
hypoplasia of optic n. and thalamus
Absence of septum pellucidum
septo-optic dysplasia
103
Cavities of the telencephalic vesicles become the
Lateral ventricles
104
Diencephalic cavity becomes the
3rd ventricle
105
Rhombencephalic Cavity becomes the
4th ventricle
106
Mesencephalic Cavity becomes the
Cerebral Aqueduct
107
Opening between the third ventricle and the lateral ventricle
Intraventricular Foramina/ Foramen of Monroe
108
Foramen that arises from the caudal part of the 4th ventricle
Communication between the ventricular system and the subarachnoid
Foramen of Magendie (median aperture)
109
Lateral Aperture
Foramen of Lushka
110
CSF is produced by the
choroid plexuses of the lateral third ventricles
111
CSF escapes the ventricular system through
4th ventricle, passes through subarachnoid space, absorbed by the arachnoid villi
112
Ventricular system is lined by
Inner ependyma of cells, outer pia mater
113
Problem in formation of the ventricular system
Congenital Hydrocephalus
114
Peak time of neuronal proliferation
3-4 mo
115
Sites of proliferation
Ventricular and subventricular zone
116
Proliferative units are produced by
symmetrical divisions of stem cells
117
Proliferative units later enlarge by
asymmetrical division of the stemcells before migration
118
Blast cells (pluripotential) multiply in __ region producing ___
Periventricular reigion, neuroblast & glioblast
119
As the cells undergo their last division, they will now begin to migrate way from the periventricular area on the __ cell
Transient glial cell
120
Guide the migration
Transient glial cell/ Radial glial cells
121
Peak time of neuronal migration
3-5 months
122
Cerebrum neuronal migration
redial migration: Cerebral cortex, deep nuclei
123
Cerebellum neuronal migration
Radial migration: Purkinje cells, dentate nuclei
Tangetial migration: external---internal granule cells
124
Synaptic reduction
pruning
