Health Sciences 2700A/B Lecture Notes - Lecture 3: Low Birth Weight, Fetal Alcohol Spectrum Disorder, Corpus Luteum
19 Sep 2016
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Chapter 3: prenatal development, birth, and the newborn. Once every 28 days, ovum bursts from ovaries and is drawn through the fallopian tubes. Corpus luteum releases hormones that prepare lining of uterus to receive fertilized ovum while ovum is travelling. If pregnancy does not occur, corpus luteum shrinks and lining of uterus is discarded two weeks later through menstruation. Male produces 300 million sperm/day in the testes located in the scrotum. Periods of prenatal development (first trimester): zygote. 2 weeks fertilization implantation critical period start of placenta. Outer ring called trophoblast provide protective covering and nourishment. Trophoblast forms membrane called amnion which encloses developing organism in amniotic fluid. End of 2nd week another protective membrane is formed called the chorion (surrounds amnion). Villi burrow into uterine lining and placenta is formed. Placenta connected to organism by umbilical cord delivers blood and nutrients: embryo. 6 weeks groundwork laid for all body structures and internal organs sensitive period.
