ACB 330 Lecture Notes - Lecture 10: Amniotic Sac, Heparin-Binding Egf-Like Growth Factor, Epiblast

• School: U of S
• Department: Anatomy and Cell Biology
• Course: ACB 330
• Professor: Kulyk William

Document Summary

Rophoblast: outer cells form into 1 syncytium this erodes uterine lining to enable implantation. Uterine endometrium secretes isp2 that digests z. pellucida. Blastocyst binds to uterine lining by using: hb-egf. Outer layer: expands by fusion secretes proteases erodes uterine lining ensuring implantation. Epiblast: closer to uterine lining: fluid accumulates here forming amniotic cavity. Amniotic cavity splits into amniotic ectoderm and embryonic epiblast. Proliferating hypoblast cells migrate down to form primary yolk sac. Implantation begins during secretory phase and ends in gravid phase o the menstrual cycle. Extra-embryonic reticulum forms between yolk sac and cytotrophoblasts. Line inner surface of cytotrophoblasts + outer layer of yolk sac. Cavities in reticulum fuse and form chorionic cavity. Lower part of primary yolk sac pinches off and dies, forming smaller secondary yolk sac. Narrow connecting stalk for 2ndary yolk sac/embryonic disk/amnion. Trophoblasts villi acquire central core or mesoderm 2ndar chorionic villi. Gastrulation: transforms the bilaminar disc into a trilaminar disc embryo.