Lect 30 Flashcards
pregnancy can be divided into what 4 stages
- initiation
- gestation
- parturition
- lactation
site of fertilization
- oviduct
- normally occurs in upper third (ampulla)

fertilization must occur within what time frame after ovulation
24 hours
how does female reproductive tract aid in sperm migration
- contraction of myometrium
- upward contraction of oviduct smooth muscle
-
Allurin released by mature eggs
- chemoattractant for sperm to reach egg in ampulla of oviduct
upon sperm passage through female reproductive tract, process of what occurs
-
capacitation: or activation
- surface characteristics of sperm are altered
- cholesterol withdrawal
- surface prodteins redistributed
- calcium influx -> increase motility
- surface characteristics of sperm are altered
sperm motility in the cervical canal requires what pH? What makes this pH
- alkaline
- alkaline secretions from prostate gland
- estrogen makes mucus water
sperm transported is assisted by myometrial contractions. what is responsible for this
- prostaglandins in ejaculate
- estrogen-primed tissue
capacitated sperm penetrate the corona radiata, contact the zona pellucida and undergo what reaction
acrosome reaction

sperm contain receptors that bind to what protein that in turn triggers the acrosome reaction
ZP3 protein
what is the acrosomal reaction
- acrosomal enzymes digest zona pellucida creating a pathway to the plasma membrane of the ovum

sperm fusion to ovum’s membrane is mediated by
- binding of fertilin on sperm head to integrin receptor on ovum membrane -> zona reaction
What is the zona reaction
- release of cortical granules containing enzymes that degrade ZP3 proteins and harden zona pelucida
- prevent polyspermy
- signals ovum for completion of 2nd meiotic division
formation of female pronucleus and male pronucleus is termed
fusion
blastocyst is composed of what two cells
- trophoblasts cells: become placenta
- inner cell mass: become embryonic structure

blastocyst implants in endometrial lining by means of enzymes released by
trophoblast
Progesterone levels from corpus luteum peak 6-8 days from ovulation converting uterus to secretory gland. what is secreted? What effect does this have on optimal time for implantation
- glycogen and lipid required for implantation
- relaxes myometrium
- **due to progesterone action, days 20-24 of regular 28 days cycle are optimal period for implantation
implantation of blastocyst occurs in what 3 stages
- apposition
- adhesion
- invasion
only after implantation is completed, is hCG detectable in maternal serum, 8-11 days after conception. what is its function
- hCG will rescue the corpus luteum at this time
most ectopic pregnancies occur within the
fallopian tube
placenta is well established and operational how long after implantation
5 weeks
what is the organ of exchange between maternal and fetal blood that performs the functions of the digestive system, respiratory system and kidneys for the fetus
placenta
what hormones does the placenta secrete
- hCG: human chorionic gonadotropin
- maintains corpus luteum until placenta takes over function in last two trimesters
- estrogen
- progesterone
function of hCG
- maintains pregnancy
- stimulates corpus luteum to secrete progesterone and estrogen
- when the placenta secretes estrogen and progesterone, hCG levels decline and corpus luteum regresses
- what pregnancy tests detect
when do levels of hCG peak
- levels peak between 9-12 weeks gestation
What is the most important estrogen in pregnancy
Estriol
estrogen during pregnancy requires what for synthesis
both fetus and placenta
functions of estrogen during pregnancy
- increased growth of myometrium - muscles for labor
- development of ductile system of breasts
- stimulates prolactin release by anterior pituitary
- relax and soften pelvic ligaments
- inhibits lactation
sources of progesterone during pregnancy
- elevated throughout pregnancy
- first 6-12 weeks -> corpus luteum
- after 12 weeks -> placenta
progesterone synthesis during pregnancy requires what
maternal cholesterol
Progesterone function during pregnancy
- conversion of uterus to secretory gland readying for implantation
- formation of cervical plug
- inhibition of myometrial contraction
- inhibition of prostaglandin synthesis in uterus
- development of alveolus and lobule in breast
- inhibit lactose synthesize