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Question 1

Label each as a postive or negative regulator of GnRH release: dopamine, serotnin, B-endrophin, norepinephrin, and leptin.

Answer 1

Question 2

What are the two phases of the menstrual cycle and how long does each one usually last?

Answer 2

Each cycle lasts 28 [to 35] days with two phases -

follicular [proliferative]

luteal [secretory] of approximately 14 days each.

Question 3

Where does 95% of estrogen (estradiol) come from?

Answer 3

comes from ovaries

Question 4

How does the midcycle LH surge effect follicular cells?

Answer 4

It causes them to change their steroid production from estrogen to progesterone

Question 5

What exactly causes the switch in steroid production during the LH surge?

Answer 5

caused by increased expression of CYP11A1 and 3β-hydroxysteroid dehydrogenase conversion of cholesterol to progesterone.

Estrogen is decreased by downregulation of aromatase.

Question 6

Where do female androgens come from?

Answer 6

Female androgens come from adrenal glands, ovaries, and peripheral conversion of androstenedione and DHEA to testosterone

Question 7

How are females protected from virilization and conversion of testosterone to DHT?

Answer 7

by higher levels of SHBG

Question 8

What is Inhibin B and Inhibin A a marker of and what is each one controlled By?

Answer 8

Inhibin B

Marker of: Granulosa cell function

Regulated By FSH

====================

Inhibin A

Marker of: Corpus luteun function

Regulated By LH

Bc B is after A so ofc its going to be longer (FSH)

Question 9

What hormones regulate the follicular phase (day 5-13)?

Answer 9

FSH stimulates follicle recruitment and growth, and estrogen synthesis

Before selection of the follicle for ovulation, granulosa cells respond only to FSH.

As the follicle matures cAMP increases, upregulating LH receptors, allowing both LH and FSH stimulation of granulosa cells .

its called follicle stimulating hormone so it makes sense

Question 10

What causes ovulation of day 14?

Answer 10

LH surge

Question 11

What causes the begining of the luteal phase and what increases in production?

Answer 11

Begins with corpus luteum formation

Increasing progesterone and estrogen production by the corpus luteum.

Question 12

What does the LH receptor activation in the luteal phase allow the production of and what is this converted to?

Answer 12

LH receptor activation allows theca cells to synthesize androstenedione, which is converted to 17β-estradiol by aromatase in granulosa cells

Question 13

What prevents resting primordial follicles from entering folliculogenesis?

Answer 13

AMH

Question 14

What are the two cells that antral follicles form?

Answer 14

. The mural granulosa cells - the basal membrane separates the granulosa cells from thecal cells. This layer is steroidogenic and forms the corpus luteum after ovulation.
2. The cumulus cells surround the oocyte [called cumulus oophorus or corona radiata]. The cumulus cells have gap junctions with the oocyte. Cumulus cells are released with the oocyte at ovulation. They allow easier capture of the oocyte by fimbria of the oviduct.

Question 15

What begins on day 1 of the menstrual cycle?

Answer 15

15-20 large antral follicles start their gonadotropin (FSH)-dependent growth.

Question 16

What happens to FSH levels by day 3 of the menstrual cycle?

Answer 16

FSH levels decrease, leading to the death of most follicles until only the one with the most FSH receptors remains, known as the dominant follicle.

Question 17

What occurs by midcycle (day 14) in the menstrual cycle?

Answer 17

The dominant follicle becomes a large preovulatory follicle.

Question 18

What role do gonadotropins play in the development of the dominant follicle?

Answer 18

Stimulation by gonadotropins turns the dominant follicle into a steroidogenic gland, activating both thecal and granulosa cells.

Question 19

What do thecal cells produce, and what receptors do they express?

Answer 19

Thecal cells express LH receptors and produce androgens.

Question 20

What do thecal cells produce under LH stimulation in large antral follicles?

Answer 20

Thecal cells produce androstenedione.

Question 21

What effect does the LH surge have on aromatase and estrogen production?

Answer 21

The LH surge inhibits aromatase, decreasing estrogen production.

Question 22

How does LH affect progesterone synthesis in granulosa cells?

Answer 22

LH increases the expression of StAR protein and enzymes, stimulating granulosa cell synthesis of progesterone.

Question 23

What substances does the oocyte synthesize in antral follicles?

Answer 23

The oocyte synthesizes cyclin dependent kinase-1 (CDK1) and cyclin B.

Question 24

What causes meiotic arrest in the mature oocyte?

Answer 24

Meiotic arrest is caused by elevated cAMP levels in the mature oocyte.

Question 25

How does cAMP affect the cyclin B–CDK1 complex (MPF) in the oocyte?

Answer 25

cAMP-PKA phosphorylation inactivates the cyclin B–CDK1 complex (MPF).

Question 26

What role does cGMP from cumulus granulosa cells play in the oocyte?

Answer 26

cGMP from cumulus granulosa cells inhibits oocyte phosphodiesterase, keeping cAMP levels elevated.

Question 27

What does the LH surge induce during the periovulatory period?

Answer 27

The LH surge induces the rupture of the dominant follicle and ovulation of the cumulus-oocyte complex.

Question 28

What happens to the dominant follicle at ovulation?

Answer 28

At ovulation, the dominant follicle presses against the ovary wall, forming a stigma.

Question 29

How do inflammatory cytokines and hydrolytic enzymes contribute to ovulation?

Answer 29

The LH surge induces inflammatory cytokines and hydrolytic enzymes to break down the wall at the stigma.

Question 30

What occurs to the cumulus-oocyte complex in the antrum after ovulation?

Answer 30

The cumulus-oocyte complex becomes free-floating in the antrum.

Question 31

What role does LH play in the behavior of cumulus cells during ovulation?

Answer 31

LH stimulates cumulus cells to release hyaluronate, which absorbs water and causes the cumulus to enlarge, making it easier for capture by fimbria.

Question 32

What happens to the blood vessels and thecal cells after ovulation?

Answer 32

After ovulation, blood vessels and thecal cells invade the granulosa cells.

Question 33

What do granulosa cells secrete after ovulation, and what is its effect?

Answer 33

Granulosa cells secrete angiogenic factors that increase the blood supply to the new corpus luteum.

Question 34

What does the mid-cycle LH surge allow the oocyte to do?

Answer 34

The mid-cycle LH surge allows the oocyte to complete meiosis I.

Question 35

What is the process of ovulation?

Answer 35

Ovulation is the rupture and release of the oocyte complex from the ovary into the fallopian tube for fertilization.

Question 36

What transition does the oocyte make due to the LH surge?

Answer 36

The LH surge induces the oocyte to progress from prophase I to metaphase II of meiosis.

Question 37

How does LH affect gap junctions between cumulus cells?

Answer 37

LH closes gap junctions between cumulus cells, decreasing cGMP levels to the oocyte.

Question 38

What is the effect of decreased cGMP on the oocyte?

Answer 38

Decreased cGMP allows phosphodiesterase to degrade cAMP.

Question 39

How does reduced cAMP affect PKA activity and meiosis I?

Answer 39

↓ cAMP reduces PKA activity, allowing MPF (mitotic promotion factor) to initiate nuclear division of meiosis I.

Question 40

What happens to the secondary oocyte during meiosis?

Answer 40

The secondary oocyte (called an egg) arrests in metaphase II due to MAPK activity.

Question 41

What triggers the completion of meiosis II and formation of the haploid gamete?

Answer 41

Fertilization leads to the degradation of MAPK, allowing the completion of meiosis II to form the haploid gamete.

Question 42

What is Mittelschmerz?

Answer 42

(“Middle hurts”) transient mid-cycle ovulatory pain that Can mimic appendicitis