Neuro development Flashcards
describe the stages of neurogenesis at day 18
formation of the notochord at the midline
neural plate develops from overlying ectoderm - neuroectoderm
by day 20 of neurogenesis what has developed
neural crest
neural floor
where is the floorplate located
above the notochord
describe the stages of neurogenesis at days 22 and 24
neural plate folds inwards
the neural plate closes:
closes at the roofplate neural crest cells
in neurogenesis what does each part of neurogenesis cell become
anterior end - brain
neural tube near somites - spinal cord
neural crest - major components of PNS
lumen of the tube - ventricles (CSF)
where does the high degree of patterning occur and by what
neural tube
morphogens
what occurs out of anterior-posterior patterning
proliferation and segmentation generate the early spinal cord and 3 primary vesicles:
brainstem
midbrain
forebrain
what are Hox genes
family of transcription factors
establish segmentation along anterior-posterior axis
how do we know that cell fate can be induced
tissue from pigmented to non-pigmented amphibian embryo
secondary axis developed, mixed origins
transplanted cells instructed host cells
what happens if there is a lack of Shh
optic vesicles are generated on the dorsal side
leads to loss of ventral identity
cyclopia
what and where are neural precursor cells
neuroepithelial progenitor cells
neural tube
what do neural precursor cells form
the ventricular zone
what connects the ventricular and pial surface
radial glia
how do neural precursors divide and where and what does it produce
asymetrically
ventricular zone
generates new progenitors and postmitotic neuroblasts
where is the ventricular zone
the inner most layer of the neural tube
where do neuroblasts migrate from and to and what to occurs
from the marginal zone to the pial surface
differentiate into neurons
where are glia generated from
neuroepithelium cells
what occurs to glioblasts if they remain attached to the lumen
become ependymal cells - produce CSF
what occurs to glioblasts if they migrate to the marginal layer
form astrocytes - maintenance and repair
or oligodendrocytes - myelination
where are interneurons born
ganglionic eminences
what is fasciculation
the embryonic body doesn’t know the whole route but navigates from one stepping stone to the next one
features of guidance signals
effectively guides growing processes in the embryo
can be attractive or repulsive
short/long range
act via concentration gradients
features of diffusible guidance signals and name them
act as gradient
long-range
netrin
semaphorin
features of non-diffusible guidance signals and name them
short-range
substrate derived
can be presented on target cells
cadherins
ephrins
