01:119:116 Lecture Notes - Lecture 17: Polarity In Embryogenesis, Archenteron, Filopodia
23 Oct 2018
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Will eventually become anus: archenteron fuses with blastocoel wall (1) forms digestive tube with mouth & anus (a) now is gastrula w/ 3 germ layers. Covered with cilia (aid with feeding & movement: gastrulation in frogs, highlights . In vertebrates, each germ layer contributes to distinct set of structures *fig. 47. 9: bilaterally symmetrical animals have three major axes: dorsal/ventral, right/left, posterior/anterior, cell movements beginning gastrulation occur on dorsal side of blastula (gray crescent, blastopore (open end of archenteron) will become anus, se(cid:395)ue(cid:374)(cid:272)e of eve(cid:374)ts *fig. Inner cell mass- cluster of cells that become embryo proper (1) source of embryonic stem cell lines: blastocoel- hollow area, gastrulation takes over ~ 1 week (during second and third weeks) Inner cell mass forms flat disc w/ 2 layers (1) epiblast (outer) (2) hypoblast (inner) (3) embryo develops almost entirely from epiblast cells. Chorion- formed from trophoblast cells, surround embryo and all other membranes.
