Week 7 Handout Answer Key

Week 7 Handout Answer Key - TA: Manely Leilah Yafeh Week 7...

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TA: Manely Leilah Yafeh Week 7 Handout 1. List the main effects of the placental hormones and sketch a graph of their levels throughout pregnancy. Human Chorionic Gonadotropin : first measurable hormone of pregnancy; rescues corpus luteum to maintain progesterone secretion; secretion peaks at the end of the first trimester and falls to 10% throughout pregnancy Human Placental Lactogen : Primary role is to support fetal growth by inducing diabetogenic symptoms in the mother. 4% of pregnant women develop gestatational diabetes. Increases glycogenolysis, gluconeogenesis, and promotes insulin resistance (via insulin receptor downregulation/desensitization) in the mother, therefore reserves glucose stores for the fetus and causes ketoacidosis in the mother; Also, may play a secondary role in mammary development due to a similar structure to GH and PRL. However, no secretion of hPL in pregnant women does not cause any adverse symptoms. Progesterone : Absolutely necessary to maintain pregnancy; Decreased secretion leads to miscarriages; Progesterone inhibits contractility of uterine smooth muscle. Estrogen : contributes to breast glandular structure; causes early morning sickness; estrogen increases uterine contractility; estrogen:progesterone ratio may contribute to the induction and maintenance of labor Relaxin : “Ripens” or softens the cervix and pubic symphysis; promotes decidual angiogenesis; acts synergystically with progesterone to inhibit uterine contractions CRH : signals the induction of labor via a positive feedback pathway 2. Which main hormones demonstrate aberrant secretion in the maternal system during pregnancy? Increased PRL; No Gonadotropin secretion; Increased TH secretion; Increased PTH secretion; Incrreased insulin secretion; Increased ACTH, increased glucocorticoids, normal mineralcorticoids, increased adrenal cortex androgens 3. What is the proposed hypothesis for the induction of parturition (labor and birth) in humans? Placental CRH diffuses into the fetal and maternal circulatory systems, stimulating the fetal and maternal anterior pituitaries to secrete ACTH, which stimulate cortisol secretion from the adrenal cortex in both the fetus and mother. In this case, cortisol acts as a stimulatory signal, which acts on both the fetal and maternal hypothalami to increase ACTH secretion. This positive feedback pathway induces labor. CRH increases PGF2 synthesis, increases oxytocin receptors,
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Week 7 Handout Answer Key - TA: Manely Leilah Yafeh Week 7...

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