Flashcards in Fertilization etc Deck (30):
Pregnancy Stage 1?
Fertilization: methods of assisting sperm
Contractions of myometrium/oviduct sm mm move sperm,
Allurin attracts sperm to egg in ampulla,
Cervical mucous thins/↑ pH
Sperm Capacitation is?
Initiated thru tract:
Cholesterol w/draw from head,
Surface proteins redistrib,
Ca2+ influx ↑ motility
Sperm route thru follicle?
Corona radiata -> zone pellucida -> ovum cyto
Acrosomal Rxn is?
Sperm receptors bind ZP3 in zona pellucida ->
acrosin released from sperm ->
allows entry into zona
Zona Reaction is?
sperm fertilin binds ovum integrin receptor ->
Zona degrades ZP3 receptors/harden zona -> prevents polyspermy
Pregnancy Stage 2?
Fertilized ovum -> blastocyst -> luteum
Blastocyst made of what type cells? (2)
1) Trophoblasts (form w/ endometrium to make placenta)
2) Inner cell mass (become embryo)
Blastocyst implants endomet how?
enzymes make hole for implant ->
nutrients released for embryo
Progesterone role in implantation?
∆ uterus to secretory gland ->
Days 20-24 optimal
Pregnancy Step 3?
Human Chorionic Gonadotropin:
Hormone from placenta -> maintains corpus luteum -> stim luteum secretion of prog/est until placenta takes over
Secreted days 8-11 of conception
Fxn of placenta?
1) digestive, respiration, renal for fetus
2) prevents immun rejection
3) endocrine hormone secretion (hCG, est, prog)
Estrogen in pregnancy?
Estriol most important
Requires fetus and placenta for synth
Urine estrogen marker for fetal health
Estrogen role during pregnancy?
↑ myometrium growth for labor
↑ breast ducts
Stim prolactin release
Softens pelvic ligaments
Progesterone in pregnancy?
wks 6-12 from luteum
wk 13 on from placenta
Synth requires maternal cholesterol
Progesterone role in pregnancy?
∆ uterus to secretory gland
inhib PG synth
inhib lactose synth
Gestation Stage 2?
maternal physical ∆s support pregnancy
↑ blood vol, CO, resp, excretion, etc
Uterine ∆ for 2rd trimester?
Prog ↓ -> uterus more excitable
Cervix relaxes via Relaxin from luteum/placenta
Gestation Stage 3?
Labor and estrogen?
1) links cells for coordinated contractions
2) ↑ myo response to oxytocin
3) ↑ PGs for cervical ripening
Labor and Oxytocin?
Stored in post pituitary,
Circulating levels don't rise but myo oxytocin receptors ↑↑
Labor and Corticotrophin-Releasing Hormone (CRH)?
Preps fetus to live:
Fetal CRH ↑ -> ↑ fetal ACTH -> ↑ fetal DHEA ->
↑ conversion into estrogen in placenta
fetal ACTH also ↑ cortisol -> matures lungs
CRH in maternal placenta is "clock"
↑ CRH -> early delivery
↓ CRH -> late delivery
Labor and Inflammation?
Uterine stretch and macrophages from ↑ pulmonary surfactants activate NF-kB in uterus
NF-kB stim inflamm cytokines/PGs ->
↑ cervical softening
Bacteria, allergic rxn, multiples can trigger labor
Labor positive feedback?
pressure of fetus ↑ oxytocin
Stages of labor? (3)
1) cervical dilation
2) delivery of baby
3) delivery of placenta
Gestation Stage 4?
Prolactin stims alveolar
W/draw of placental steroids stim lactation
Synth'd by pituitary
Release stim by Thyrotropin-releasing hormone
Release inhib by Dopamine
Prolactin block ovulation how?
(Lasts for 7 months)
Inhib GnRH release -> inhib LH/FSH
Antagonizes action of LH/FSH on ovaries
Milk Lactoferrin does?
blocks growth of harmful bacteria in milk