19- Neurulation animation

This animation illustrates neurulation dynamically and with a three-dimensional perspective. Beginning with the bilaminar disc, the primitive streak advances dorsally and then recedes. As the embryo grows, the neural plate enlarges dorsally and the neural groove deepens. The neural folds meet in the midline near the center of the embryo to form the neural tube. Neural tube closure then proceeds both rostrally and caudally. If closure is incomplete caudally, a child is born with spina bifida. If closure is incomplete rostrally, the brain will not develop. Approximately 40 pairs of somites flank the neural tube. By embryonic day 28, the central nervous system is completely enclosed within the embryo.