BIOL 300 Lecture Notes - Lecture 2: Primitive Streak, Germ Layer, Chym-Fm
Document Summary
Translation of greek and latin roots ect-: outside. A long axial rod, located dorsal to the digestive tract. It is composed of a wall of fibrous connective tissue surrounding cells and/or a fluid-filled space. Early stage of embryonic development in which the 3 germ layers differentiate, cells migrate from the outer surface of the embryo to inside the embryo, and (in many taxa) the early gut is formed. Earliest opening in the developing embryo, this opening forms in the blastula at the beginning of gastrulation. Cells from the outer surface of the embryo migrate through the blastopore during gastrulation. (note: in the chick the cells migrate through the primitive streak instead. ) Pertaining to eggs with large quantities of stored yolk. The early embryonic gut this space is lined with endoderm. The region of the somites (epimere mesoderm) that gives rise to the vertebrae and ribs.
