PSY 361 Chapter Notes - Chapter 4: Amniotic Sac, Umbilical Cord, Prenatal Development
25 Oct 2016
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*gestation: period of development b/t conception & birth. *gestational age: age of an unborn baby, usually is dated from first day of last menstrual period. Prenatal (prebirth) has three stages: germinal fertilization 2 weeks then begins to implant in uterine lining . *blastocyst: fluid filled sphere , floats in uterus until 6th day after fertilization , umbilical cord , . Then forms embryotic disk , ectoderm , endoderm , mesoderm , amniotic sac : embryotic 2-8 weeks. Look at figure 4. 3 weeks after conception (cid:272)a(cid:374)"t sur(cid:448)i(cid:448)e outside (cid:449)o(cid:373)(cid:271) (cid:894)mis(cid:272)arriage(cid:895) *spontaneous abortion: natural explosion from the uterus of an embryo that. 3/4 miscarriages occur in 1st trimester: fetal- 8 weeks- birth. *cephalocaudal principle: head to tail , upper parts of body grow before lower parts . *proximodistal principle: near to far, parts of body near center develop before the outer ones . *teratogen: environment agent i. e. a virus , drug or radiation that can interfere with normal development of the fetus.
