PSY 2105 Chapter Notes - Chapter 3: Headache, Venezuelan Equine Encephalitis Virus, Syphilis
30 Jan 2015
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Stages of prenatal development: conception fertilization of the egg by the sperm. Formation of the zygote; 24 hour window: period of the zygote conception to the second week. Prenatal development already underway by the time a woman suspects she may be pregnant: period of the embryo third to eighth week. Also the most delicate and vulnerable period. Ectoderm outside layer; becomes the nervous system, sensory receptors, and skin. Mesoderm middle layer; becomes circulatory system [heart begins to beat at 4 weeks], muscles, bones, excretory system, and reproductive system. Endoderm inner layer; becomes digestive system and respiratory system. Placenta where blood vessels of mother and child intertwine. Amnion clear fluid sack that protects embryo. The umbilical cord is the connecting link between the fetus and the placenta, and transports oxygen/nutrients to the fetus from the placenta; and returns waste products from the fetus to the placenta. A full term is 38 40 weeks.
