FMLY 1010 Lecture Notes - Lecture 14: Yolk Sac, Umbilical Cord, Placenta

• School: University of Manitoba
• Department: Family Social Sciences
• Course: FMLY 1010
• Professor: Christine A.Schippers

Document Summary

Germinal stage = first stage of prenatal development, beginning at conception and ending at implantation (approximately 2 weeks) Cells specialize into those that will become body, and those that will support development. By day 4, zygote contains dozens of cells. Day 5, cell becomes blastocyst = hollow, fluid-filled ball. Cells inside blastocyst will become the embryo once they clump together. Day 6 or 7, blastocyst comes into contact with uterine wall. Day 12, blastocyst completely buried in uterine tissue. Implantation = attachment of blastocyst to uterine wall. Placenta = specialized organ that allows substances to be transferred from mother to embryo (and back) without their blood mixing. For(cid:373)ed whe(cid:374) (cid:272)ells fro(cid:373) (cid:271)lasto(cid:272)yst"s outer wall (cid:272)o(cid:373)(cid:271)i(cid:374)e with (cid:272)ells of uteri(cid:374)e li(cid:374)i(cid:374)g. Secretes chemical messages (hormones) to stop menstrual periods and keep placenta connected to uterus. Allow bones of pelvis to become more flexible. Umbilical cord = organ that connects the embryo to the placenta.