BIO 11 Lecture Notes - Lecture 2: Primitive Streak, Neural Tube, Gastrulation
Document Summary
Gastrulation: the rearrangement of the cells of bilaminar embryonic disc to form the trilaminar embryonic disc. Primitive streak: thin groove on the dorsal surface of the epiblast, which runs along the cephalic-caudal line of embryo. It establishes the head and tail regions, the right and left sides, and the dorsal and ventral surfaces of the embryo. When the primitive streak has developed, gastrulation begins. It gives a pathway for epiblast cells to move into and underneath the primitive streak - ingression. 1st layer replaces hypoblast and becomes the endotherm. After the embryo undergoes folding, the ectoderm is on the external surface - forms the epidermis. Neurulation: the first major event of organogenesis which develops of nervous system (brain and spinal cord) Ectoderm thickens and create a neural plate, closes itself off and breaks off, forming the neural tube. Anterior end of the neural tube will develop into three enlarged areas called the primary brain vesicles.
