Chapter 12 Summary

Chapter 12 Summary - Chapter 12 Pregnancy and Birth 1...

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Chapter 12: Pregnancy and Birth 1) Fertility a) Conception – The incredible journey (1) A women’s sexual desire peaks at or just before ovulation to increase chances of pregnancy (2) 30% of intercourses result in conception, many of those conceptions spontaneously abort (3) Sperm usually last only 24 hours, a few can last 3 days, and less than 1% can last a week (4) Sperm have no guidance and only respond if they detect an ovum (5) Once an ovum is detected, sperm swim violently towards the center (6) One sperm can fertilize the ovum, once that happens the ovum defends itself from the other sperm (7) The fertilized ovum is a zygote (8) 12 hours after conception, the zygote will double, and will continue to double every 23 hours. It is now called a blast cyst (9) The blastocyst enters the uterus 3-4 days later (10) The uterus releases a chemical allowing the blastocyst to attach to uterine wall (11) 3 layers form, the ectoderm, mesoderm and endoderm form, these begin the formation of tissues (12) 2-8 weeks after conception, the blastocyst becomes an embryo (13) The amnion begins to form around the embryo, which fills with amniotic fluid (14) The placenta is connected to the uterine wall and supplies blood and nutrients to the fetus (15) The umbilical cord connects the fetus to the placenta transfer fluids to and from the fetus (16) Fraternal twins come from two fertilized zygotes (17) Identical twins come from the complete separation of one zygote b) Early signs of pregnancy (1) Missing a period (2) Breast tenderness, excessive urination and morning sickness (3) During pregnancy, some women experience vomiting and nausea
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c) Pregnancy testing: Confirming the Signs (1) Most pregnancy tests detect a chemical called human chorionic gonadotropin (2) Home pregnancy tests must be taken before the 12 th week of pregnancy but not too soon (3) Radioimmunoassay blood tests are the most accurate pregnancy test. They can detect hCG
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This note was uploaded on 03/24/2009 for the course ANT 2301 taught by Professor Gravlee during the Fall '08 term at University of Florida.

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Chapter 12 Summary - Chapter 12 Pregnancy and Birth 1...

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