Oogenesis and Pregancy

Question 1

What chromosomes are in oogonium?

Answer 1

Diploid: 46 single chromosomes.

Question 2

When does meiosis I take place?

Answer 2

Begins in fetal life, completes meiosis I just prior to ovulation.

Question 3

In what phase are primary oocytes arrested prior to ovulation?

Answer 3

prOphase before Ovulation. 46 sister chromatids.

At ovulation will continue and split into 2ndry oocyte and polar body.

Question 4

In what phase are secondary oocytes arrested?

Answer 4

metaphase II - haploid, 23 sister chromatids.

Question 5

When does the progression of arrested 2ndry oocytes in metaphase II occur?

Answer 5

Fertilization. 23 sister chromatids –> Ovum w/ 23 single chromatids and a polar body.
If does not occur within 1 day, 2ndry ooctye degenerates.

Question 6

What are the steps leading up to ovulation?

Answer 6

1. Increase in estrogen increases GnRH receptors on AP.
2. Estrogen surge stimulates LH release –> ovulation.
3. Increase in temperature bc of progesterone.

Question 7

What is mittelschmerz?

Answer 7

Transient mid-cycle ovulatory pain, classically associated with peritoneal irritation - due to follicular swelling/rupture/fallopian tube contraction.

Question 8

What can mittelschmerz present similarly to?

Answer 8

Appendicitis.

Question 9

Where does fertilization most commonly occur and when?

Answer 9

Ampulla (upper end) of fallopian tube. Within 1 day of ovulation.

Question 10

When does implantation occur?

Answer 10

Within 6 days after fertilization

Question 11

What secretes hCG? When is it detectable?

Answer 11

Synciotrophoblasts secrete. Detectable in blood 1 week after conception, in urine on home test in 2 weeks.

Question 12

What allows initation of lactation after delivery?

Answer 12

Fall in progesterone and estrogen disinhibits lactation.

Question 13

What is the effect of suckling?

Answer 13

Required to maintain milk production: nerve stimulation –> oxytocin and prolactin.

Question 14

What is the role of prolactin in lactation?

Answer 14

Induces and maintains lactation and inhibits GnRH (decr reproductive function).

Question 15

What is the role of oxytocin in lactation?

Answer 15

Assists in milk letdown, also promotes uterine contractions.

Question 16

What supplementation do exclusively breastfed infants require?

Answer 16

Vitamin D supplementation.

Question 17

What immunological benefits does breastfeeding have?

Answer 17

• Contains maternal immunoglobulins (conferring passive immunity, mostly IgA).
• Macrophages, lymphocytes

Question 18

What disease does breastfeeding decrease the risk of in children?

Answer 18

Infections, asthma, allergies, DM, and obesity.

Question 19

What diseases does breastfeeding decrease the risk of for mothers?

Answer 19

Decr maternal risk of breast and ovarian cancer

Question 20

What causes decrease estrogen production near menopause?

Answer 20

Age-linked decline in number of ovarian follicles.

Question 21

What is the avg age of menopause?

Answer 21

51 (earlier in smokers)

Question 22

What can menopause before age 40 indicate?

Answer 22

premature ovarian failure

Question 23

What occurs in the 4-5 yrs prior to menopause?

Answer 23

Abnormal menstrual cycles.
Source of estrogen (estrone) after menopause becomes peripheral conversion of androgens… leads to increased androgen production, hirsutism.

Question 24

What is the diagnostic hormonal finding for menopause?

Answer 24

Increased FSH due to loss of negative feedback from estrogen.

Question 25

What hormonal changes are seen in menopause?

Answer 25

Decr estrogen

Way increased FSH, incr LH, incr GnrH.