Exam 1: Lecture 1 Flashcards
Name the 6 development events
1) formation and patterning of neural tube
2) neurogenesis
3) migration
4) Cell differentiation
5) Synapse formation
6) Connectivity maturation
The process by which embryonic tissue that will become neural tissue is SPECIFIED is…
neural induction
Embryonic neural tissue is the ___ ___ which gives rise to the ____ ____ which gives rise to the whole CNS and the ___ ___ which gives rise to PNS.
neural plate
Neural tube - CNS
neural crest- PNS
What is the process by which different regions start to appear in the neural plate/tube?
patterning of neural plate/tube
what is the process of formation of the neural tube.
neurulation
What is the process by which neural PROGENTIORS (stem cells) rapidly divide to make other progenitors.
progenitor proliferation
What are other names for proliferative zone?
germinal and ventricular zone
ventricular zone: apical and basal identification
apical is on inner space
basal is facing outside
What determines fate of progeny in progenitor division?
plane of axis
apical domain: where the division line is
Process by which neural progenitors (neural stem cells) produce neurons
neurogenesis
Process by which glial cells are generated by neural progenitors
gliogenesis
neuroblasts move out birthplace in proliferative zones of neural tube to final position in NS.
Migration
radial or tangential
Process by which newly born cells acquire specific cell type identity and become SPECIALIZED IN FUNCTION
cell differentiation
circuit formation and synapse formation: how do they do it
specialization at axons/dendrites GROWTH CONES allow them to navigate the tissue, following guidance cues, until they find counterpart
Process by which axons/dendrites reach target
guidance/navigation
Axonal growth cones transform into ___ ___
presynaptic specializations
Dendrites receive synapses at
different locations (not just final ends)
Synaptogenesis
synapse formation
Circuit/connectivity maturation
process newly form neural circuits reach an stable state )usually referring to acquisition of functionality, but stable state, doesn’t mean final state.
Maturation can extend during long periods
What is MATURATION, not plasticity?
synaptic pruning synaptic rearrangement natural cell death over-produced neural cells myelination
Standardized system that provides unified developmental chronology of vertebrate embryo (23 stages)
stages are delineated through the development of landmark structures not by size/number days of development, which vary
Human-60 days, then fetus
mouse-E16
rat-E17.5
Early Development
induction, neural tube formation, (stage 9-12)
neural tube patterning/segmentation, (stages 12-15)
neural progenitor proliferation (stages 9-22)
mid development
- neurogenesis starts stages 23 through birth)
late neurodevelopment
stages 5 and 6. After GW26, continues after birth, throughout childhood
After induction, what two processes occur SIMULTANEOUSLY?
patterning and neurulation
becomes regionalized and folds inward
neural plate induction is specification of the ______ from _____, which occurs in 3-laminat disk of gastrula.
neuroectoderm
ectoderm
gastrulation ends with
neurulation
inductive (neural) signals
chordin, noggin, follistatin
come from underlying mesoderm, NOTOCHORD
vertical
since not all mesoderm tissue has same neural inductive capacity, ________
determines fate in neural plate
position of overlying tissue with respect to notochord
anti-neural signals
BMP4, Wnt
FLANKING ECTODERM (lateral/planar) induction
repress neural, promote ectodermal
inner cell mass are embryonic cells that do what? What are these specific cells called?
generate entire embryo
totipotent stem cells
line right by the inside semicircle
What is part of the BILAMINAR DISK that gives rise to the embryo?
Epiblast
What originates in embryonic part of placenta?
hypoblast - around the epiblast
Exocoelomic cavity
that middle yok sac thing
Main events of the 2nd week of development
formation of exocoelomic membrane
stuff goes around
Endometiral gland
What happens in early embryogenesis (before neural induction):
Days 14-15
14-15: primitive streak in epiblast. Epiblasts cells migrate inward from the primitive node through the streak (will form mesoderm and endoderm)
What happens in early embryogenesis (before neural induction):
Days 16:
ingressing epiblast cells form ___ and ___. At the midline, will form specialized mesoderm structure called ______
form mesoderm and endoderm
notochord
What happens in early embryogenesis (before neural induction):
Gastrulation
bilaminar to trilaminar embryo
Signals from ______ are required for induction of neural tissue
primary organizers
What is tissue/structure that exert difrentiation effect on the surrounding tissue and make it develop into a different structure (e.g. inducing and entire body axis, or inducing neural fate in the ectoderm).
Primary organizer
In animals ______ is the primary organizer
in amphibians ____ of the blastopore is the primary organizers
primary node (end of primity streak)
dorsal lip
What are chemical signals that emanate from a specific tissue and spread away from the source creating a concentration gradient that determines the fate of cells exposed to the gradient?
morphogens
Neural plate induction
When does the neural plate appear?
What does it cover?
Day 17
thickening of embryonic ectoderm over axial mesoderm
Notochord forms only where?
midline rostral to primitive node and caudal to oropharyngeal membrane.
Main point: not present along whole axis
What is the axial mesoderm anterior to notochord?
prechordal plate (PCP)
Though both the notochord and PCP are patterning the neural plate they have
different effects
Are FGFs inductive or antineural?
can promote induction at early stages or inhibit neural at later stages
Neural fate signals (review)
Chordin
Noggin
Follistatin
FGF
Inhibit neural fate (review)
BMP4, Wnt, FGFs