pregnancybirth

pregnancybirth - Chapter 7 Conception, Pregnancy, and...

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Chapter 7 Conception, Pregnancy, and Childbirth
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Conception Sperm Meets Egg: The Incredible Journey The egg is released from the ovary into the body cavity. The cervix secretes mucus that flushes the passageways to prepare for arrival of the sperm. Sperm are capable of swimming about 1 inch per hour.
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Sexual Intercourse - Man on Top
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Structure of the Sperm
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Conception: In the Fallopian Tube Conception usually occurs in the outer third of the fallopian tube. The egg is surrounded by a thin, gelatinous layer called the zona pellucida . Sperm swarm around the egg and secrete an enzyme called hyaluronidase . This enzyme dissolves the zona pellucida, permitting one sperm to penetrate the egg.
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Improving the Chances of Conception Time intercourse so it occurs around the time of ovulation. Keep a basal body temperature chart. Best to have intercourse about four times during the week in which the woman is to ovulate. Best position for conceiving is with the woman on her back. Lubricants and/or suppositories may kill sperm or block their entrance into the uterus.
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Following Conception The fertilized egg, called the zygote , continues to travel down the fallopian tube. About 36 hours after conception, it begins the process of cell division. For the first eight weeks of gestation the conceptus is called an embryo. From then until birth it is called a fetus . The nine-month pregnancy is divided into three equal trimesters.
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Development of the Conceptus During the first eight weeks the inner part of the ball of the cells implanted in the uterus differentiates into layers: Ectoderm - will form the nervous system and the skin. Endoderm - differentiates into the digestive system and the respiratory system. Mesoderm forms between the ectoderm and the endoderm; differentiates into muscles, skeleton, connective tissues, reproductive system, circulatory system.
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Support System for the Embryo The placenta is the mass of tissues that surrounds the conceptus early in development and nurtures its growth. Human chorionic gonadotropin ( hCG ) is a hormone manufactured by the placenta. The umbilical cord is formed during the fifth week of embryonic development. Amniotic fluid maintains the fetus at a constant temperature and cushions it against possible injury.
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During the first trimester the small mass of cells implanted in the uterus develops into a fetus. The woman can feel movement, and the physician can detect the fetal heartbeat, by the 18th week, during the second trimester. During the seventh month, in the third trimester, the fetus turns in the uterus to assume a head down position. If the turning does not occur by the time of
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This note was uploaded on 04/27/2008 for the course BIO 50.230 taught by Professor Wassmer during the Fall '07 term at Bloomsburg.

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pregnancybirth - Chapter 7 Conception, Pregnancy, and...

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