Development of the neural tube Flashcards
what is the first identifiable feature in the formation of the neural tube?
the notochord
what is the process of gastrulation?
cells near the primitive streak of the blast invaginate into the embryonic disc
produces the 3 germ layers
what is the notochord?
signalling centre, transient structure, plays a major role in embryo folding and controls the direction of embryo folding
what happens at the beginning of week 3 of development?
the ectodermal germ layer broadens at the cephalic area (where the future head will be)
notochord arises from this area
which region does the notochord arise from?
the cephalic area
what do the cells of the notochord contribute to after fetal life?
cells of the nucleus pulposus of the IVD after fetal life
what do signals from the notochord do?
induce development in the neural plate and the overlying ectoderm
signals involved are the proteins noggin and chrodin
what are the 2 important protein signals involved from the notochord?
proteins noggin and chordin
what kind of signals are proteins noggin and chordin?
negative regulators of development
presense activates inhibition of other molecules
what does the absence of BMP4 mean?
the patterning of the neural tube and somites can occur
what would happen if BMP was present?
no neural tube would form
what do the cells of the neural plate make up?
neural ectoderm
what is the depression in the middle of the 2 neural folds called?
neural groove
what happens to the lateral edges of the neural plate and it lengthens?
they start to elevate to make two neural folds with a depression in the middle
when is the neural tube formed?
when the folds eventually meet together and fuse
what happens after the neural tube is formed?
the hole of the tube sinks down into the body of the embryo and the surface ectoderm will appear over the top of the newly formed tube
what does the neural tube go on to form?
the brain and the spinal cord
what mechanism controls the bending of the neural plate?
-cell wedging (microtubules and microfilaments changing cell shape, cell cycle)
-hinge points (median hinge point and dorsolateral hinge point)
-extrinsic forces (pushing the surface ectoderm, adhesion point with the notochord)
what are the mechanical controls of the bending of the neural plate?
cells become a bit more wedge shape which pushes the tube to form
what process is the most important in the bending of the neural plate?
formation of hinge points
when in development does the lateral edges of the neural plate become elevated?
day 19
where are the hinge points?
the median hinge point - at the region of the neural groove
dorsolateral hinge point- dorsolateral side of the embryo help close the tube
what are neural crest cells?
highly migratory cells that form at the time of new relation
move all through the embryo body and give rise to varied structures
what kind of structures do the neural tube cells give rise to?
craniofacial structures
melanocytes
dorsal root ganglia
teeth
where does fusion start?
cerviacle region of the embryo
proceeds in a cephalic and caudal direction simultaneously
what are the anterior and posterior neuropores?
the ends of the neural tube which have not yet fused