L33 Psych 321 Lecture Notes - Lecture 7: Endoderm, Ectoderm, Twin
5 Mar 2019
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Period of the zygote: weeks 1-2, twins, extra zygote split (monozygotic, dizygotic two eggs released (tendency to have dz twins is hereditary; trait of mother releasing two eggs at once) Period of the embryo: weeks 3-8, after implantation, germ disc develops a neural tube, placental material starts from the zygote, embryo: 4 weeks, embryo: 6 weeks. Period of the fetus: weeks 9-38, last 12-15 weeks is finishing , so babies may be delivered during this time and survive, overview of fetal development, age of viability 32 weeks newborn can survive at this point. Influences on prenatal development: general risk factors, nutrition. Poor nutrition leads to a risk of prematurity or low birth weight. Folic acid is fundamentally important to the developing fetus child may develop spina bifida without it: stress. High levels of anxiety throughout pregnancy is connected to low birth weight. Indirect effects stress can decrease the oxygen level to the fetus, increase the activity level of the fetus.
