Pregnancy Parturition & Lactation - RM Flashcards
What is the purpose of follicular cells?
protect and nurture egg
Where do sperm bind glycoproteins as the first step of fertilization?
zona pellucida
What is the acrosomal reaction? What triggers it?
- triggered by rise in intracellular calcium from sperm binding glycoprotein
- leads to fusion of acrosome with sperm plasma membrane and release of hydrolytic enzymes in sperm
What allows the sperm to penetrate the zona pellucida?
hydrolytic enzymes released dissolve zona pellucida and whip-like motion of tail pushes sperm forward
What is the cortical reaction?
- exocytosis of granules that previously lay immediately beneath the egg’s plasma membrane
- enzymes released lead to hardening of zona pellucida to prevent entry of other sperm
What 3 things does the rise in intracellular calcium trigger?
acrosomal reaction, cortical reactoin, expulsion of second polar body (completion of second round of meiosis)
What is the product of the male and female pronuclei fusing called?
zygote
What hormone regulates the one degree increase in basal body temperature at ovulation?
progesterone
In what time frame after ovulation does fertilization have to occur to be successful?
within 24 hours
How long does it take to optimize the uterus for nourishment for the blastocyst to implant?
around a week
Why do you need the corpus luteum still in the 1st 8 weeks of pregnancy? What hormone does it produce?
- to sustain the blastocyst since the placenta hasn’t fully developed yet
- produces hCG, which substitutes for LH at this time since they are homologous and share receptors
How does sperm make its way to ampulla of fallopian tube? (female contribution, male contribution)
- fallopian tube contraction in response to oxytocin released during orgasm
- fallopian tube contraction in response to prostaglandins in seminal fluid
What produces hCG? What does hCG do in males?
synctiotrophoblasts in blastocyst
stimulates testes to produce testosterone
What does early fetal nutrition? Later fetal nutrition?
early–endometrial lining
later–diffusion through placenta
What hormones does the placenta supply?
steroid hormones (progesterone, estrone, estradiol, estriol), hCG, somatomammotropins (related to growth hormone and promotes mammary gland development)
What indicates the normal development and health of placenta?
rapid rise in estriol
What contribution from the fetus do you need to make estrogen in the placenta?
DHEA-S (androgen) from fetal adrenal and liver
What is maternal response to pregnancy related to blood volume, MAP, CO, and alveolar ventilation?
blood volume–increases to meet increased demands
MAP–decreases due to vasodilation from steroid hormone and adaptive changes of kidney or remains around normal after rise in 3rd trimester
CO–increased primarily in 1st trimester from increased SV
Alveolar ventiliation–increased tidal volume from steroid’s effects on respiratory centers, decreased maternal arterial PCO2
What can trigger parturition?
increased fetal production of cortisol
increased ratio of estrogen/progesterone
increased sensitivity to contractile stimulus
What keeps the uterus quiet in most of pregnancy?
progesterone, relaxin
What are Braxton Hicks contractions?
baby’s head stretches cervix, excites fundic contraction by release of oxytocin, contraction pushes baby’s head further down, stretches more, repeats (ouch)
What initiates contractions? What sustains them?
prostaglandins initiates, oxytocin sustains
What increases the number of oxytocin receptors on myometrial tissue during pregnancy?
estrogen
What is the Ferguson reflex?
increase in oxytocin release in response to distension of cervix
What produces relaxin? What does relaxin do?
produced by corpus luteum, placenta
increased production in labor may soften/dilate cervix
What does Ru486 do?
inhibits progesterone to make uterus more contractile and cause abortion
What two functions does oxytocin have? what is it released in response to?
milk letdown, uterine contractility
suckling
What does prolactin do?
promotes and maintains milk synthesis
in response to suckling
Why doesn’t prolactin start having an effect till after birth happens?
estrogen and progesterone from placenta inhibit it, once it is delivered, this inhibition is released and prolactin has effect
What is the functional secretory unit of the breast?
alveolus
What permissive hormone stimulates milk production besides prolactin?
cortisol
How is colostrum different from milk?
lower volume, lower fat, higher antibodies
