Developmental neurobiology Flashcards
briefly describe gastrulation
the epiblast forms 3 layers - ectoderm (neural plate), mesoderm (notocord) and endoderm
which germ layer does the nervous system arise from
ectoderm
describe neural induction
the neural plate border has a bunch of signals.
as neurulation is forming, the signals converge, inducing cells in the neural plate to become neurons, and the non-neural ectoderm cells to form the epidermis
describe neurulation
the neural plate folds, forming the neural tube. it zips inside out to close
-if it doesnt close properly, neural tube defects can occur
describe neurogenesis
pial surface: synthesis
apical surface: everything else
symmetrical: one APC forms 2 APC’s
asymmetrical type I: when two new cells are made, one turns into an APC, the other turns into a neuroblast than a neuron
asymmetrical type one: as with before, but before turning into a neuroblast it forms a basal progenitor cell
describe neuron migration
neuroblasts climb up APC’s, and then are distributed into the cortex as neurons. newer neurons are distributed outside
describe neuron patterning
different parts of the neural tube swell to become ventricles, which form different parts of the brain (fore/mid/hind)
signals/growth factors occur in different places. leading to formation of different neuron patterns
describe axon guidance
growth cone
- receptors:bind to environmental ligands, which can influence growth cone growth
- cues may be repulsive/attrctive, contact/distance
describe synaptogenesis
requires two neurons to make contact, for contact to be stabilised by cell to cell interactions, and for the neuron to be sufficiently mature (ie. have machinery)
-modulated by use of syanpse
describe dendritic growth
- length increases after birth
- pyrimidal has one apical dendrite and multiple basal
when does gliogenesis occur
after neurogenesis
where do astrocytes and oligodendrocytes come from
neural plate
where do microglia come from
immune system
where do schwann cells and satelite cells come from
neural crest cells.
describe how neural crest cells form
neural plate border cells induced to become neural crest cells
what must happen for neural crest cells to migrate
epithelial-mesenchymal transition
4 parts of epithelial-mesenchymal transition
less cell-cell adhesion
less cell matrix adhesion
cells lose polarity
cell shape changes from round to triangular
neural crest cells in teh trunk form
sympathetic and dorsal root ganglia
pigment cells
adrenal medulla
difference between sympathetic and dorsal root ganglia
dorsal root: perpendicular to spinal cord
sympathetic: parallel to spinal cord.
describe 6 steps of sympathetic chain ganglia formation
neural crest cells migrate via somites to the dorsal aorta
cells are dispersed along aorta
cells aggregrate into ganglia
ganglia move dorsally, towrads spinal cord.
preganglionic neurons synapse with ganglion cells
ganglion cells synapse with targets
what is neuroblastoma?
cancer of sympathetic ganglion cells.
describe neurotransmitter plasticity
ganglion neurons may change from secreting noradrenaline to acetylcholine
what did drosophilia show
discovery of axon guidance molecules
what did c elegans show
role of specific neurons
axon regenration
what did zebrafish show
adult neurogenesis
what’s special about mice
mammals, model neurodevelopmental disorders
describe human organoids
human embryonic stem cells are exposed to growth factors, which can cause them to develop into an organ
pros of human organoids
might better be able to model human organs than animal models
cons of human organoids
not exact replicas of human organs - in petri dish, no blood supply and hence microglia
ethical issues.
