Female Pregnancy Flashcards
What increases during ovulation?
2 Days before ovulation there is an increase in:
LH (6-10 fold)
FSH (2-3 fold)
***ovulatory surge of LH is NECESSARY***
What does LH do?
LH converts granulosa and theca cells to progesterone producing cells
When can fertilization occur?
Fertilization can occur if intercourse takes place within a 3-day period prior to the day of ovulation
But also cannot occur later than 1-day post ovulation
Why does ferilization occur 3 days prior to the day of ovulation but no later than 1 day post ovulation?
it is 3 days prior because sperm can survive up to 3 days in the female reproductive tract
it is no later than 1 day becausee the secondary oocyte disintegrates 12-24 hours after ovulation
What is capacitation?
final maturation enabling the them to swim quickly and fertilize egg
-involves recognization of molecules in the OM of the sperm head
What occurs one day after ovulation?
Fertilization
sperm and egg combine to make a zygote
What occurs 2-4 days after ovulation?
Cell Division
The zygote begins to divide as it travels through the oviduct
what occurs 4-5 days after ovulation?
Blastocyst reaches uterus
** read more about this
What is a dizygotic twin?
Fraternal Twins;
develop from two seperate oocytes fertilized at the same time
What is a monozygotic twin?
Identical Twins;
two individuals develope from one fertilized oocyte; they have identical genomes
What is a conjoined twin?
monozygotic twins whose bodies are joined to a varying extent
How does implantation or nidation of the blastocyte work?
Trophoblast cells produce enzymes that allow blastocyst to “eat its way” into the endometrium
How do trophoblasts work ?
Trophoblast cells secrete hCG (human chorionic gonadotropin) to maintain the moher’s corpus luteum (to make progesterone until the fetal placenta can take over)
It produces enzymes to implant into uterine wall on 6th day after fertilization.
NOTE: approx 75% of lost pregnancies are due to failure of implantation
What keeps the pregnancy going BEFORE the placenta is formed?
hCG (made by blastocyst) maintains corpus lutuem
-feeds back into the ovaries
*takes a couple months for the placenta to form
why is the corpus luteum needed to synthesize progesterone?
Early pregnancy:
- corpus luteum synthesizes progesterone to keep the endometrium intant
- progesterone, estrogen, inhibin: feedback suppression to pituitary
what are the hormones the placenta makes?
hCG : maintains corpus luteum
estrogen : uterine myometrium (growth, oxytocin receptors) breasy ducts
progesterone : suppress uterine contractions, cervical plug, milk glands
PTHrP (parathyroid hormone-related peptide) : mobilizes mother’s bone calcium
CRH : fetal lung maturation
What are the parts of the sperm ?
Has 3 main parts: head, mid piece and tail (flagellum)
Head is composed of acrosome and a nucleus
Midpiece is the mitochondria
How many sperm fertilize an egg ?
Fertilization usually in the Fallopian tubes
-Only approx. 100 sperm reach this point
How does sperm fertilize an egg ?
Sperm tunnel through barriers (acrosomal enzymes, receptors)
- Penetrate outer layer granulosa cells; corona radiata
- penetrate protective glycoprotein coat; zona pellucida
**First sperm binds to receptor, fuses with egg “wins” - prevents polyspermy**
What are disorders of implantation ?
ECTOPIC PREGNANCY
[def] : implantation in a different site than the posterior wall of uterine cavity (occurs 0.25-1.0%)
2 types:
- tubal pregnancies (endometriosis, prior surgery, pelvic inflammatory diseases)
- ovarian pregnancies
what is placenta previa ?
embryo implant close to the cevrvix, normal embryonic development, placenta partially covers cervical anal
BASICALLY - placenta partially or wholly blocks the neck of the uterus, thus interfering with normal delivery of a baby
what are the sites of ectopic pregnancy?
intramural (2%)
isthmic (25%)
ampullar (54%)
ovarian (0.5%)
cervical (0.3%)
infundibular (17%)
What do pregnancy tests detect ?
Look for hCG in urine
>human chorionic gonadotropin (hCG) is secreted by the blastocyst
**NOT THE MOTHER
What are the hormonal trends during pregnancy ?
0-3 months :
> estrogen and progesterone are low but increasing
> hCG is at a drastic peak
3 months - delivery :
> estrogen and progesterone levels continue to rise
>hCG decreases and plateaus, becoming nonexistant at delivery
