Physiology and Endocrinology of Uterine & Ovarian Cycles

Question 1

What is a normal menstrual cycle range?

Answer 1

25-35 days

Question 2

True or False: Menstruation to ovulation varies, whereas ovulation to menses is generally14 days (life span of corpus luteum)

Answer 2

True

Ex: In a 35 day cycle, it’s the follicular phase that’s long… when it’s a 25 day cycle, it’s the follicular phase that’s short

Question 3

the remnant of the ovarian follicle

Answer 3

corpus luteum

Question 4

development of follicle = which phase?

Answer 4

follicular phase

Question 5

rupture of follicle and release of ovum = which phase?

Answer 5

ovulation

Question 6

follicle fills with blood and becomes corpus luteum, while ovum travels via uterine tubes = which phase?

Answer 6

luteal phase

Question 7

atrophy of corpus luteum results in decline of progesterone which supported uterine lining and thus sloughs off = which phase?

Answer 7

menstruation

Question 8

_______________ is released from arcuate and preoptic nuclei in hypothalamus

Answer 8

Gonadotropin releasing hormone (GnRH)

Question 9

GnRH binds the GnRH receptor on ________________ and promotes synthesis and release of LH and FSH

Answer 9

anterior pituitary

Question 10

How does GnRH binding promote the synthesis and release of BOTH FSH and LH?

Answer 10

Rapid pulsation of GnRH = promotes luteinizing hormone (LH)

Slower pulsation of GnRH = promotes follicle stimulating hormone (FSH)

Question 11

Theca cells are stimulated by ________

Answer 11

LH

Question 12

Granulosa cells are stimulated by __________

Answer 12

FSH and LH

Question 13

Theca cells stimulate the synthesis of progesterone and androgens; this is known as _____________

Answer 13

steroidogenesis

Question 14

Under FSH guidance, granulosa cells do what?

Answer 14

1) convert androgens into estrogens
2) produce activins, inhibins, follistatin

Question 15

Activins ____________ (increase/decrease) FSH and estrogen production

Answer 15

increase

Question 16

Inhibins ___________ (increase/decrease) FSH and estrogen production

Answer 16

decrease

Question 17

Follistatin ___________ (increases/decreases) activin function

Answer 17

decreases

Question 18

True or False: Theca cells are not well-vascularized, thus do not receive many LDLs

Answer 18

False

Well vascularized and thus get lots of LDL→ leads to high steroidogenesis rate under LH stimulation

Question 19

Theca cells produce androstenedione and testosterone (and a bit of progesterone, though insignificant), but cannot make estrogens because why?

Answer 19

they lack aromatase enzymes

Question 20

True or False: Unlike theca cells, granulosa cells have poor access to blood, thus must make cholesterol de nova and rely largely on theca cells

Answer 20

True

Question 21

________ converts androgens to estrogen in granulosa cells

Answer 21

Aromatase

Note: Androgens must diffuse from theca cells to granulosa cells

Question 22

______ promotes expression of aromatase

Answer 22

FSH

Question 23

Estrone is converted into estradiol via _____________

Answer 23

17 Beta-hydroxysteroid dehydrogenase

Question 24

Primordial germ cells undergo mitosis and develop into oogonia within fetus and then develop into primary oocytes and begin their first meiotic division but arrest in __________ (and will remain so until ovulation during puberty)

Answer 24

prophase

Question 25

Primordial follicle (fetus) will either mature into a primary follicle or undergo ___________ – this will continue throughout life

Answer 25

atresia (die off)

Question 26

Primary follicles will develop into secondary follicles only after ____________

Answer 26

puberty

Note: due to high exposure to FSH and LH

Question 27

Granulosa cells proliferate and begin to convert the _________ produced by theca cells to estradiol

Answer 27

androgens

Question 28

________ cells differentiate into
theca interna and externa

Answer 28

Stromal

Question 29

Secondary follicles develop into ____________ follicles, characterized by:

• Theca layers expand
• Antrum appears and filled with fluid
• Increases in size and volume of fluid
• Increased production of estradiol

Answer 29

tertiary/antral

Question 30

Just before __________, the antral follicle(s) will develop into Graafian follicle(s)

Answer 30

ovulation

Note: At this point, granulosa cells form distinct layers, there is a large amount of estradiol within the follicle (20x that of blood), and it is enriched with growth factors, oxytocin, steroids, peptides

Question 31

_________ factors contribute to the selection of dominant follicle at ovulation

Answer 31

Growth

Question 39

The follicular phase is characterized by initially _______ (high/low) amounts of:

• LH
• estrogen
• progesterone,
• inhibin

but ________ (high/low) amounts of FSH (lack of inhibition)

Answer 39

LOW,

HIGH

Question 40

FSH will act on recruited follicles and stimulate them to grow into preantral stage (secondary follicle) between days ______

Answer 40

3-5

Question 41

Dominant follicle is selected on days ________

Answer 41

5-7

Note: This is based on SIZE and STEROIDOGENIC ACTIVITY (more resources are directed towards this follicle)

Question 47

Endometrium is composed of what type of cells?

Answer 47

secretory columnar epithelium