KINE 3340 Chapter Notes - Chapter 5: Fetal Alcohol Spectrum Disorder, Fallopian Tube, Blastomere
29 May 2014
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Document Summary
Teratogen-environmental agent that causes harm to the embryo. Factors of how much damage teratogen will cause depend on amount of exposure, baby"s genetic makeup and time of exposure. 3 major phases of human organism: the germinal (fertilization and implantation), the embryonic period and fetal period. Consist of release of the oocyte from the ovary into the uterine tube where fertilization happens. Next 3 days the zygote will divide forming a blastomere (group of cells) as it proceeds down uterus. When zygote cleavage (mitotic divison) reaches 12-15 blastomeres it is called morula. After morula enters uterus it becomes a blastocyte. 6 days after fertilization it attaches to endometrium(posterior wall of uterus). During second week it sinks beneath endometrium completeting implantation. Teratogen during preembryoic period can kill it. Organ and support systems start to form. Zygote forms inner layer of cells called endoderm and outer layer of cells are subdivided to form ectoderm and mesoderm.
