Fertilization etc Flashcards
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?
Implantation:
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 ->
glycogen/lipds
Relaxes myometrium
Days 20-24 optimal
Pregnancy Step 3?
hCG secretion
hCG is?
Released when?
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
Levels ↑↑
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 Inhib lactation
Progesterone in pregnancy?
Levels ↑
wks 6-12 from luteum
wk 13 on from placenta
Synth requires maternal cholesterol
Progesterone role in pregnancy?
∆ uterus to secretory gland cervical plug inhib contractions inhib PG synth inhib lactose synth
Gestation Stage 2?
38 wks
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?
Parturition (labor/delivery/birth)
Labor and estrogen?
↑ 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?
Lactation:
Prolactin stims alveolar
W/draw of placental steroids stim lactation
Prolactin?
Lactogenesis hormone
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
Milk Bifidus Factor does?
promotes growth of helpful bacteria
