Oogenesis and Pregancy Flashcards
What chromosomes are in oogonium?
Diploid: 46 single chromosomes.
When does meiosis I take place?
Begins in fetal life, completes meiosis I just prior to ovulation.
In what phase are primary oocytes arrested prior to ovulation?
prOphase before Ovulation. 46 sister chromatids.
At ovulation will continue and split into 2ndry oocyte and polar body.
In what phase are secondary oocytes arrested?
metaphase II - haploid, 23 sister chromatids.
When does the progression of arrested 2ndry oocytes in metaphase II occur?
Fertilization. 23 sister chromatids –> Ovum w/ 23 single chromatids and a polar body.
If does not occur within 1 day, 2ndry ooctye degenerates.
What are the steps leading up to ovulation?
- Increase in estrogen increases GnRH receptors on AP.
- Estrogen surge stimulates LH release –> ovulation.
- Increase in temperature bc of progesterone.
What is mittelschmerz?
Transient mid-cycle ovulatory pain, classically associated with peritoneal irritation - due to follicular swelling/rupture/fallopian tube contraction.
What can mittelschmerz present similarly to?
Appendicitis.
Where does fertilization most commonly occur and when?
Ampulla (upper end) of fallopian tube. Within 1 day of ovulation.
When does implantation occur?
Within 6 days after fertilization
What secretes hCG? When is it detectable?
Synciotrophoblasts secrete. Detectable in blood 1 week after conception, in urine on home test in 2 weeks.
What allows initation of lactation after delivery?
Fall in progesterone and estrogen disinhibits lactation.
What is the effect of suckling?
Required to maintain milk production: nerve stimulation –> oxytocin and prolactin.
What is the role of prolactin in lactation?
Induces and maintains lactation and inhibits GnRH (decr reproductive function).
What is the role of oxytocin in lactation?
Assists in milk letdown, also promotes uterine contractions.
What supplementation do exclusively breastfed infants require?
Vitamin D supplementation.
What immunological benefits does breastfeeding have?
- Contains maternal immunoglobulins (conferring passive immunity, mostly IgA).
- Macrophages, lymphocytes
What disease does breastfeeding decrease the risk of in children?
Infections, asthma, allergies, DM, and obesity.
What diseases does breastfeeding decrease the risk of for mothers?
Decr maternal risk of breast and ovarian cancer
What causes decrease estrogen production near menopause?
Age-linked decline in number of ovarian follicles.
What is the avg age of menopause?
51 (earlier in smokers)
What can menopause before age 40 indicate?
premature ovarian failure
What occurs in the 4-5 yrs prior to menopause?
Abnormal menstrual cycles.
Source of estrogen (estrone) after menopause becomes peripheral conversion of androgens… leads to increased androgen production, hirsutism.
What is the diagnostic hormonal finding for menopause?
Increased FSH due to loss of negative feedback from estrogen.
What hormonal changes are seen in menopause?
Decr estrogen
Way increased FSH, incr LH, incr GnrH.
