development part 1 Flashcards
Development
the complex process of turning a single fertilized egg into a fully-‐formed animal
initially, what are embryos?
undifferentiated sheets of cells.. (organisms have polarity, where does this come from?)
‘primitive streak’
establishes the axes of the developing embryo: divides left from right and anterior from posterior
The neural folds fuse to create the ______
Neural tube
How do the neural folds fuse?
from the middle outwards
Problems with neural tube development: Anencephaly & spine bifida.
At the rostral end problems with the process cause anencephaly at the caudal end, closure defects cause spine bifida.
differentiation
the process where a less specialized cell becomes a more specialized type of cell. Largely a process of customizing transcription, tuning gene expression to create different cell types.
the closed neural tube expands into ______
3 bulges or “three primary brain vesicles”
What is neural development all about?
elaboration of the three primary brain vesicles into more complex structures.
three primary brain vesicles
secondary vesicles of the forebrain
As the telencephalon (‘cerebrum’) develops it expands ______ and ______ to sit to the developing mid- and hind‐brain.
laterally and caudally.
dorsal.
Differentiation of the telencephalon
Differentiation of the telencephalon
Differentiation of the telencephalon
Differentiation of the telencephalon
A mouse with a spontaneous genetic mutation in the ‘reeler’ gene has _______. Specifically, _______
disorganized brain structure.
lamination is altered.
for circuts to form correctly several things must happen…
- ) Neurons must be born in the right place and time (neurogenesis)
- ) Axonal projections must grow enabling them to target the appropriate cells
- Specific synaptic connections must form
Transcription
factors
proteins that rgulate the expression of genes.
They can positivly and negitivly regulate target gene expression, ot work in concert with a widerange of co-regulators to finely tune gene expression.
Radial glial cells
project from the ventricular to pial surface.
Neuroblasts, born via horizontal cleavage at the ventricular zone, migrate up the radial glia, forming the layers of the cortex: subplate, cortical plate, layer VI, V, IV, III, II, I.
Note: deeper layers first!
Unlike most projection neurons, interneurons and oligodendrocytes
migrate _______ into the cortex
Laterally
Areas of cortex are distinguishable by ______ features
cytoarchitectural
Transplantation experiments demonstrate that one type of cortex (visual) can be differentiated into another (somatosensory).
This suggests that the ______ helps define specific cytoarchitecture in the developing cortex
input recieved.
Growing retinal axons must choose three things correctly
- Pathway: Which way to turn at
the optic chiasm? - Target: When you get to the
correct structure (here the
thalamus), which nucleus do
innervate? - Address: Of all the neurons
within the target nucleus, which
one(s) do you synapse with?
