01:119:116 Lecture Notes - Lecture 17: Inner Cell Mass, Yolk Sac, Archenteron
22 Apr 2016
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Document Summary
Normal cell cycle resumes + rate of cell division slows down. Cellular and tissue-based processes by which animal body takes shape. Occurs during last two stages of embryonic development. Gastrulation: movement of cells from the blastula surface to the interior of the embryo. Morphological process by which hollow blastula becomes a layered embryo called a gastrula. Mesoderm forms between ectoderm and endoderm. Diploblasts (cnidarians and other radially symmetrical) only ecto and endo. Triploblasts (vertebrates and other bilaterally symmetrical) ecto, endo, and meso. Involces invagination infolding of a sheet of cells into embryo. Second opening later becomes mouth deuterostomes. Mesenchyme cells at vegetal pole migrate into blastocoel later secrete. Vegetal pole buckle inwards invagination endoderm cells form archenteron mesenchyme cells at tip of archenteron produce filopodia (thin extension) Filopodia contract drags archenteron across blastocoel blastopore. Archenteron fuses will blastocoel wall digestive tube with mouth and anus gastrula has 3 germ layers + covered in cilia (will function in feeding and movement)
