Repro - Physiology (Oogenesis, Ovulation, Pregnancy, and Menopause)

Question 1

When do primary oocytes begin meiosis I? When do they complete it?

Answer 1

Primary oocytes begin meiosis I during fetal life and complete meiosis I just prior to ovulation

Question 2

What is the state of meiosis in oocytes prior to ovulation? To which type of oocytes does this apply?

Answer 2

Meiosis I is arrested in prOphase I for years until Ovulation (primary oocytes)

Question 3

What is the state of meiosis in oocytes prior to fertilization? To which type of oocytes does this apply?

Answer 3

Meiosis II is arrested in METaphase II until fertilization (secondary oocytes); Think: “an egg MET a sperm”

Question 4

How long does fertilization have to occur? What happens if does not occur in this time?

Answer 4

If fertilization does not occur within 1 day, the secondary oocyte degenerates

Question 5

Draw out the stages/process of oogenesis, labeling the following: (1) Replication (interphase) (2) Meiosis I (3) Meiosis II (4) Oogonium diploid (2N, 2C) (5) Primary oocyte diploid (2N, 4C) (6) Secondary oocyte Haploid (1N, 2C) (7) Ovum Haploid (1N, 1C) (8) Polar bodies (include 4) (9) 46 sister chromatids (10) 23 sister chromatids (11) single chromosomes (12) single chromatids (13) Arrested in prophase I until ovulation (14) Arrested in metaphase II until fertilization (15) Ovum.

Answer 5

See Pg. 569 in First Aid 2014 or Pg. 522 in First Aid 2013 for visual

Question 6

Once a polar body is formed in oogenesis, what are its possible fates?

Answer 6

Polar body can degenerate or give to 2 polar bodies

Question 7

What occurrences in the menstrual cycle lead to ovulation?

Answer 7

Increased estrogen, Increase GnRH receptors on anterior pituitary. Estrogen surge then stimulates LH release, causing ovulation (rupture of follicles)

Question 8

With what change in temperature is ovulation associated? What causes this?

Answer 8

Increased temperature (progesterone induced)

Question 9

What is Mittelschermz? What are its classic associations? What other condition can it mimic?

Answer 9

Refers to transient mid-cycle ovulatory pain; Classically associated with peritoneal irritation (e.g., follicular swelling/rupture, fallopian tube contraction); Can mimic appendicitis

Question 10

Where does fertilization most commonly occur?

Answer 10

Fertilization most commonly occurs in upper end of fallopian tube (the ampulla)

Question 11

When does fertilization occur?

Answer 11

Occurs within 1 day of ovulation

Question 12

When does implantation with the wall of the uterus occur?

Answer 12

Implantation within the wall of the uterus occurs 6 days after fertilization

Question 13

What substance can be used to detect pregnancy, when, and how? What secretes this substance?

Answer 13

Syncytiotrophoblasts secrete hCG, which is detectable in blood 1 week after conception and on home test in urine 2 weeks after conception

Question 14

Draw a graph with weeks (0-40) on the x axis and hormone on the y axis. Graph and label the following hormones: (1) hCG (2) Prolactin (3) Progesterone (4) Estriol. Also, label the period of hormone release from corpus luteum versus placenta.

Answer 14

See p. 570 in First Aid 2014 or p. 523 in First Aid 2013 for visual near top left

Question 15

What disinhibits lactation after labor?

Answer 15

After labor, the decrease in progesterone and estrogen disinhibits lactation.

Question 16

What is required to maintain milk production, and why?

Answer 16

Suckling is required to maintain milk production, since increased nerve stimulation increases oxytoxin and prolactin

Question 17

What functions does prolactin serve?

Answer 17

Prolactin - Induces and maintains lactation and decreases reproductive function

Question 18

What functions does oxytocin serve?

Answer 18

Oxytoxin - Assists in milk letdown; also promotes uterine contractions

Question 19

What is the ideal nutrition for infants < 6 months old?

Answer 19

Breastmilk is the ideal nutrition for infants < 6 months old

Question 20

What are 3 important things contained in breastmilk?

Answer 20

Contains maternal immunoglobulins (conferring passive immunity; mostly IgA), macrophages, and lymphocytes

Question 21

What kind of immunoglobulin does breastmilk mostly contain, and what effect does this have?

Answer 21

Contains maternal immunoglobulins (conferring passive immunity; mostly IgA)

Question 22

What advantages does breast milk confer to the infant?

Answer 22

Breastmilk reduces infant infections and is associated with decreased risk for the child to develop asthma, allergies, diabetes mellitus, and obesity.

Question 23

What do exclusively breastfed infants require?

Answer 23

Exclusively breastfed infants require vitamin D supplementation

Question 24

What advantages does breastfeeding confer to the mother?

Answer 24

Breastfeeding decreases maternal risk of breast and ovarian cancer, and facilitates mother-child bonding

Question 25

What is the source of hCG?

Answer 25

Synctiotrophoblast of placenta

Question 26

What function does hCG serve, when, and how?

Answer 26

Maintains the corpus luteum (and thus progesterone) for the 1st trimester by acting like LH (otherwise no luteal cell stimulation, and abortion results).

Question 27

What changes in the 2nd and 3rd trimesters with regard to hCG?

Answer 27

In the 2nd and 3rd trimesters, the placenta synthesizes its own estriol and progesterone and the corpus luteum degenerates (i.e., no longer need hCG to maintain corpus luteum for progesterone)

Question 28

What is hCG’s clinical purpose, and why?

Answer 28

Used to detect pregnancy because it appears early in the urine

Question 29

What are the structural parts of hCG? What is one important thing to remember about each part?

Answer 29

Alpha subunit structurally identical to alpha subunits of LH, FSH, and TSH; Beta subunit is unique (pregnancy test detects Beta subunit)

Question 30

In what contexts is hCG elevated?

Answer 30

hCG is elevated in multiple gestations and pathologic states (e.g., hydatidiform mole, choriocarcinoma)

Question 31

What change is associated with menopause, and to what is this change linked?

Answer 31

Decreased estrogen production due to age-linked decline in number of ovarian follicles

Question 32

What is the average age of onset of menopause? In what patient population does this change, and how so?

Answer 32

Average age onset is 51 years (earlier in smokers)

Question 33

What usually precedes menopause?

Answer 33

Usually preceded by 4-5 years of abnormal menstrual cycles

Question 34

What is the source of estrogen after menopause? What effect does this have?

Answer 34

Source of estrogen (estrone) after menopause becomes peripheral conversion of androgens, increased androgens –> hirsuitism

Question 35

What is a specific marker for menopause when markedly elevated? What causes this elevation?

Answer 35

Markedly elevated FSH is specific for menopause (loss of negative feedback on FSH due to decreased estrogen)

Question 36

What are the hormonal changes associated with menopause?

Answer 36

Hormonal changes: decreased estrogen, markedly increased FSH, increased LH (no surge), increased GnRH

Question 37

What symptoms are associated with menopause?

Answer 37

Menopause causes HAVOCS: Hot flashes & Hirsuitism, Atrophy of the Vagina, Osteoporosis, Coronary artery disease, Sleep disturbances

Question 38

What can menopause before age 40 indicate?

Answer 38

Menopause before age 40 indicates premature ovarian failure

Question 39

What is the N (ploidy) and C (# of chromosomes) for each of the following cell stages in oogenesis: (1) Oogonium (2) Primary oocyte (3) Secondary oocyte (4) Ovum.

Answer 39

(1) Diploid (2N, 2C) (2) Diploid (2N, 4C) (3) Haploid (1N, 2C) (4) Haploid (1N, 1C)