BIOL 3020 Lecture Notes - Inner Cell Mass, Morula, Oviduct
11 Feb 2013
School
Department
Course
Professor
Document Summary
Early development of the zygote to a blastocyst (1st week) Fertilization in the oviduct produces zygote. Zygote undergoes cleavage as it moves along oviduct produces morula: as zygote divides, cells become smaller \ morula stays same size, movement by cilia and peristalsis present in oviduct walls. Morula develops into a blastocyst: trophoblast (outer layer of blastocyst) nourishes future embryo, fluid filled cavity for protection (absorbs shocks, resists compression, ) Blastocyst ( 100cells) implants itself in uterus lining: nourished by secretion from uterus, microvilli provide large surface area ( gas + nutrients exchange) Implantation of the blastocyst into the uterine lining (2nd week) Trophoblast secretes enzymes digest tissues and blood vessel of endometrium. Trophoblast secretes human chorionic gonadotrophin (hcg) hormone. During gestation ( length of pregnancy) growth rate is in excess. Placenta is the first organ to develop when blastocyst embeds itself in uterine lining: growth faster than embryo in early pregnancy.
