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Lecture 51
Pregnancy/Lactation
Term | Definition |
---|---|
Fertilization | in oviduct.capacitation (inc sperm motility) occurs in female reproductive tract.chemical attraction of sperm to ovum.head of sperm attaches to zona pellucida receptors. |
Fertilization cont | digestive enzymes in a chromosome breakdown zona pellucida sperm enters,zp receptors blocks second entry. |
Embryo Development | ovum starts dividing after fertilization leads to blastocyte,still surrouded by other cells-form trophoblast.in uterine wall-become placenta.folic acid needed for proper embryonic development. |
Corpus Luteum | hCG from uterus maintains corpus luteum.continues progesterone production until placenta large enough for progesterone production. |
Placental Hormones | func to maintain pregnancy. |
hCG | human chorionic gonadotropin. maintains cl after implantation.used for pregnancy tests. |
Progesterone | dec uterine contractions during gestation.dec p triggers start of contractions at parturition |
Relaxin | also dec uterine contractions.softens pelis and cervix for delivery |
Placental Functions | supply steroids for fetal cortisol exchange of gases,nutrients,waste products. inc maternal respiration and renal output. |
Parturition | child birth.exact initiator unknown. inc estrogen leads to inc uterine excitability, inc # of gap junc and inc # of oxytocin receptors. |
Progesterone | dec in most cases. in some deliveries,other factors overcome quieting effect of p on uterus. |
Oxytocin | o levels high throughout pregnancy,but low # of receptors inc # of receptors near term (estrogen effect). inc uterine contractions and cervical dilation. |
Labor | pos feedback: inc uterine pressure leads to oxytocin relase leads to inc pressure leads to prostaglandin release leads to inc oxytocin induced contractions.spinal reflex aids deliver by inc abdominal contrac head first,then shoulders,rest of body,placenta |
Lactation | milk production for newborn nutrition |
Prolactin | not a gonadotropin (does not cause hormone release). females milk secretion.prl secretion peaks at parturition. |
Breast Development | estrogen inc mammary duct size.progesterone inc mammary lobule size.prl completes structural development. |
Milk Secretion | primarily by prl.first 2 weeks are colostrum-nutrients,lactoferrin (antibiotic) antibodies.then milk-includes all essential nutrients. |
Milk Ejection | inc in oxytocin triggered by suckling.contracts mammary ducts.milk to nipple:lapped up,not sucked out.oxytocin inc uterine contractions,returns to shape |
GnRH Effects | prolactin dec gnrh release. dec fsh,dec lh,dec ovulation during breastfeeding duration. |