BIO380H5 Lecture Notes - Lecture 8: Cerebral Hemisphere, Brainstem, Medulla Oblongata
Document Summary
Bio 380 lecture 8 establishment of the basic embryonic body plan. How to develop a cylinder out of the flat trilaminar germ disk. At day 21, there is no trace of the primitive streak. As the primitive streak is regressing, the neural groove starts to form in its place. The ectodermal cells are differentiated into two cells: neural ectoderm starting from day 18, there will be some thickening in a single layer of ectoderm, which will surround the developing neural groove. The neural plate, will develop starting from the prechordal plate down towards the regressing primitive streak. The columnar ectoderm cells began to elongate and will form the neural plate, the future central nervous system. At day 21, primitive streak is almost gone, and is completely gone by day 22. The neural plate will arrange itself in a key like structure, the anterior is wider than the posterior.
