PSYC20008 Lecture Notes - Fall 2017 Lecture 7 - Morning sickness, Umbilical cord, Swaddling
20 Sep 2018
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Zygote develops small, burr-like tendrils that emerge from its outer surface. Implantation when the blastocyst reaches the uterine wall, the tendrils burrow inward a(cid:374)d tap o(cid:374) the (cid:449)o(cid:373)a(cid:374)(cid:859)s (cid:271)lood suppl(cid:455) Only half of the fertilised ova is firmly implanted. As many as half of such implants are genetically abnormal/fail to develop/burrow into a site incapable of sustaining them (unable to receive adequate blood supply) Of zygotes fail to survive this initial phase of development: embryo, embedded balls of cells begin to differentiate. Amnion watertight sac that fills with fluid, acting as a cushion, regulating temperature and providing a weightless environment. Chorion membrane surrounding the amnion and eventually becomes the lining of the placenta. Inner cell mass folds itself into three layers. Ectoderm (top layer) becomes the nervous system, the nails, teeth, inner ears, lens of the eyes and outer layer of skin. Mesoderm (middle layer) becomes the bones, muscles, circulatory system, inner layers of skin and other internal organs.
