HDE 100A Lecture Notes - Lecture 3: Antibody, Lactation, Caffeine
25 Sep 2016
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Chapter 3 prenatal development by guest lecturer megan waechter-mcmillan: germinal period about 8-10 days; the shortest period of prenatal development. They are totipotent stem cells have the potential to become anything. The egg is released, fertilized, and goes through first cleavage (the first cell division: morula by the 3rd day, there are now. 16 cells: blastocyst by the 5th day, there are hundreds of cells. Early blastocysts look more cushy with developing cells that are dividing rapidly. Later blastocysts are identified by even more cell division. The trophoblast becomes the placenta; the blastocyst cavity becomes the embryo (and later the fetus); the inner cell mass becomes the ectoderm. Implantation 6th-12th day (on average about the. 9th day); this marks the end of the germinal period. 75% of pregnancies don"t make it to implantation (will miscarriage) This can be a great danger to the mother possible organ rupture and internal bleeding can occur.
