lecture 14-15

Question 1

summarize how the central nervous system is formed and specify the major driving forces

Answer 1

After the embryonic axes have been determined during gastrulation, a ridge of cells emerges from the primitive ectoderm, giving rise to the neural plate. The neural plate contains neuroepithelial cells (which are stem cells of the whole nervous system).
After gastrulation, neurulation is next. 2 ridges, called the neural folds, emerge during neurulation and form the neural tube. Neural cell type progressively specialize under the influence of morphogens and cell-cell signaling cascades, while complex structure emerges during folding due to differences in cell cycle, adhesiveness, apoptosis and physical constraints.