Physiology of Female Reproductive System

Question 1

Follicular structures

Answer 1

Premodial follicle-> Primary follicle-> Secondary follicle-> Graafian follicle

Question 2

Of the two layers of theca cells, which makes the most hormones?

Answer 2

Theca interna

Question 3

Progesterone is made from which cells?

Answer 3

Granulosa lutein cells

Question 4

When is the corpus luteum formed?

Answer 4

After ovulation

• The antum collapses, granulosa cells becomes granulosa lutein cells and theca cells become theca lutein cells

NOTE: The follicular fluid contains a lutenization inhibitor which inhibits most of the the luteinization before the ovulation. Once the cell loses follicular fluid, we lose inhibition of the conversion of the luteinization state.

Question 5

What are the two phases of follicular growth?

Answer 5

• Stimulated
  
  • Regulated by gonadotropins and terminates in atresia or ovulation.
• Tonic or Basal
  
  • Before LH and FSH appear

NOTE: Each month about 100 follicle begin stimulate growth with 20 reaching a larger size

Question 6

What are the major characteristics of the early follicular growth phase?

Answer 6

• Rising GnRH leads to increased FSH and LH
• Increased FSH leads to increased follicular growth, aromatase, LDL and LH receptor
  
  • NOTE: We get 30% of cholesterol from plasma LDL
• Increased LH leads to increased androgen production and vasculatization of the theca interna region

Question 7

What are the major characteristics of the late follicular growth phase?

Answer 7

• LH acts on granulosa and thecal cells, FSH acts on granulosa cells
• Follicular fluid characterized by elevated levels of estradiol, progestins, LH and FSH but low androgens
• Atretic follicles charachterized by elevated androgen levels

Question 8

Aromatase is an important enzyme in ______ synthesis.

Answer 8

Estrogen

Question 9

Elevated levels of ____ can be expected when we stop making P450 aromatase.

Answer 9

Androgens because we stop converting androgens to estrogens.

Question 10

Ovarian steroid synthesis

Answer 10

Question 11

When we stimulate the follicle with LH, it stimulates the induction of more ______ protein into the mitochondria membrane.

Answer 11

StAR

NOTE: Cholesterol cross the mitochondria membrane via the StAR protein. Once in the mitochondria, cholesterol is converted to pregenelone via the P450 side chain cleavage enzyme.

Question 12

What are the two hormones that can be converted to estradiol?

Answer 12

Estrone and testosterone

NOTE: Cholesterol-> Pregenolone-> Progesterone-> 17-hydroxyprogesterone-> androstenedione->estrone-> ESTRADIOL

-OR-

Cholesterol-> Pregenolone-> Progesterone-> 17-hydroxyprogesterone-> androstenedione-> testosterone-> ESTRADIOL

Question 13

Which two cell types are required for the synthesis of follicular estrogen?

Answer 13

Theca cells

• Synthesize androgens
• Stimulated by LH
  
  • ​Leads to induction of enzymes needed for andostenedione synthesis
    
    • ​Andostenedione diffuses into the granulosa cell

Granulosa Cells

• Convert androgens to estrogens
• Stimulated by FSH
  
  • ​Leads to induction of P450 aromatase

Question 14

What is the role of SF1?

Answer 14

SF1 is a nuclear receptor that stimulates StAR in mitochondria membrane

Question 15

__________is a preadipocyte-specific nuclear receptor that regulates expression of aromatase in adipose tissue.

Answer 15

LRH-1

Question 16

The _________, a cone shaped protrusion of the follicular wall, appears just prior to ovulation.

Answer 16

Stigmata

Question 17

What events take place right before ovulation?

Answer 17

• Appearance of stigmata
• Follicular fluid has elevated estrogen, prohgestins, FSH, LH, oxytocin, plasmin and collagenase activity
  
  • Plamin degrades the basal lamina
  • Collagenase cleaves adhesive proteins
• Extensive vascularization

NOTE: These events help to weaken the follicle and prepare it for ovulation.

Question 18

Myoepithelial cells located around the basal lamina are stimulated by ________.

Answer 18

Oxytocin

NOTE: Oxytocin promotes contractions and it builds up in the follicular fluid prior to ovulation.

Question 19

If we properly weaken the area of the stigmata, we then eject an oocyte with cumulus complex, freeing it from the rest of the follicle. The rest of the follicle becomes the _________.

Answer 19

Corpus luteum

Question 20

Which enzymes serve to digest the follicular wall and weaken granulosa cell adhesion?

Answer 20

• Collagenase
• Plasmin

NOTE: The wall gives way at the weakened area forming the stigmata

Question 21

What are the 3 phases of corpus luteum development?

Answer 21

• Early luteal phase
• Advanced Luteal Phase
• Late Luteal Phase

NOTE: FSH has no direct role in corpus luteum maintenance

Question 22

What occurs during the early luteal phase?

Answer 22

• LH stimulates thecal and granulosa cell growth
• LH induces luteinization of both cell types and subsequent growth of luteinized cells
• Progesterone synthesis increases as the number of luteal cells increase

Question 23

What occurs during the advanced luteal phase?

Answer 23

• LH stimulates increased estrogen and progesterone synthesis
• Corpus luteum function depends on adequacy of follicular development before ovulation
  
  • FSH induction of adequate LDL receptor and LH receptor levels before ovulation assures sufficient steroidogenesis by the corpus luteum
  • Inadequate CL production of progesterone leads to luteal insufficiency

NOTE: FSH has no direct role in corpus luteum maintenance

Question 24

What occurs during the late luteal phase?

Answer 24

• Estrogen enduces luteolysis
  
  • ​Luteolysis leads to decreased plasma progesterone and estrogen
  • Luteolusis process continues in absence of fertilized ovum

Question 25

What is different about steroid synthesis in the follicular phase and steroid synthesis in the luteal phase?

Answer 25

**Follicular phase** * Granulosa cells stimulated by FSH **Luteal phase** * Granulosa cells stimulated by LH

Question 26

Inhibin, activin, and follistatin are secreted by the ____ of the testes and the ______ cells of the ovaries.

Answer 26

Sertoli; granulosa

Question 27

Inhibin

Answer 27

Feedback from gonads to the anterior pituatary and suppress secretion of FSH

Question 28

Activin ________ **(stimulates/inhibits)** FSH secretion.

Answer 28

Stimulates

Question 29

Folistatin binds to ____ and blocks its activity on pituatary gonadotropes to reduce FSH secretion.

Answer 29

Activin

Question 30

Which estrogen type has the most estrogenic activity?

Answer 30

E2- 17 betaestradiol

Question 31

What affect does estrogen have on the ovaries?

Answer 31

Increase function

Question 32

What effect does estrogen have on the uterus?

Answer 32

* Increased growth * Increased endometrial growth

Question 33

What effect does estrogen have on the fallopian tubes?

Answer 33

* Increases overall growth * Increases mucosal growth

Question 34

What effect does estrogen have on the breasts?

Answer 34

* Increases growth and development * Increased fat deposition * Increased stromal cell growth * Increased ductile system development **NOTE:** Estrogen increases growth and progestorone increases secretion

Question 35

What are the phases of the uterine cycle?

Answer 35

**Proliferative phase** * ​Growth of stromal and epithelial cells as well as blood vessels * Via estrogen produces **Secretory phase** * Glands become convoluted, secretion greatly increases, growth continues. * Estrogen and progesterone are being produced

Question 36

What are the stages of the cervical cycle?

Answer 36

* **Early follicular cycle** * **​**Low mucus volume and elasticity, high viscosity * **Late follicular phase** * **​**Increased mucus volume and elasticity, decreased viscosity * **Luteal phase** * **​**Similar to that of the early follicular phase * Progesterone blocks the activity of estrogen

Question 37

What are the two kinds of secretion of the cervix?

Answer 37

**Surface mucus cells** * Make a really thick mucus * Prevents things from goin gin and out **Endometrial glands** * Makes a thin high protein secretion * **High protein leds to elasticity** * Allows spermatozoa to go in **NOTE:** Estrogen stimulates cervical gland secretion

Question 38

Follicular phase in ovary= __________ phase in uterus.

Answer 38

Proliferative

Question 39

Luteal phase in ovary= __________ phase in uterus.

Answer 39

Secretory phase

Question 40

What are the phases of the vaginal cycle?

Answer 40

**Early follicular** * Predominenately basophilic cells * Decreased volume; increased viscosity **Late follicular** * Predominately cornified cells * Increased volume, decreased viscocity **Luteal** * Decreased cornified cells, increased polymorphonuclear neutrophils * Decreased volume, increased viscocity

Question 41

What are the phases of the adult menstrual cycle?

Answer 41

**Follicular phase** * Post-mentrual, proliferative, estrogenic * Follicular maturation * Proliferative endometrium **Luteal phase** * Premenstrual, secretory, progestational * Corpus Luteum Activity * Secretory endometrium

Question 42

Rise in basal body temperature is induced by \_\_\_\_\_\_\_.

Answer 42

Progesterone

Question 43

Estrogen peak in the follicular phase is the result of a switch to ___________ feedback regulation of the gonadotropins.

Answer 43

Positive

Question 44

Inhibin B is produced mainly by the \_\_\_\_\_\_\_\_\_\_\_, while inhibin A is derived mainly from the \_\_\_\_\_\_\_\_\_\_.

Answer 44

Follicle; Corpus luteum The B version inhibits FSH

Question 45

The major androgen from thecal cells is \_\_\_\_\_\_\_\_\_\_.

Answer 45

Androstenedione

Question 46

What accounts for the LH surge?

Answer 46

Positive feedback regulation from LH and FSH, stimulate the hypothalamus to release GnRH, which stimulates LH release. ## Footnote **NOTE:** FSH is inhibited by inhibin B, which is why there is no FSH surge to accompany the LH surge

Question 47

A ________ secretion of GnRH is required to stimulate pituatary secretion of gonadotropins.

Answer 47

pulsitile **NOTE:** If we give the pituatary a _tonic_ signal, it shuts down and stops secreting.

Question 48

What are the three patterns of gonadotropin secretion in women?

Answer 48

**Chichoral** * High frequency changes occuring at 1-5 hour intervals **Diurnal** * Intermittent frequency changes occuring across a 24-hr period **Trigintan** * Low frequency changes occuring across a 29-30 day period

Question 49

Estrogen feedback supresses the ______ (**amplitude/frequency**) of gonadotropin pulses. Progesterone feedback supresses the _______ (**amplitude/frequency**) of gonadotropin pulses.

Answer 49

Amplitude; frequency

Question 50

What levels of estrogen trigger a switch to positive feedback control?

Answer 50

\>300 pg/ml for \>24 hours

Question 51

What are the major types of oral contreceptives?

Answer 51

**Estrogen-progesterone** * Suppresses ovulation and supports secondary sex organ function * Used to regularize cells in some subjects **Progesterone mini pill** * Blocks estrogen induced cervical mucus changes **The estrogen "morning after" pill** * A high dose estrogen treatment * Believed to function by interfering with implantation * It is believed that the implantation site is chosen by the level of estrogen at the site **NOTE:** Oral contraceptives suppres the cyclical pattern of all major reproductive hormones

Question 52

Addition of _________ increases plasma half-life of oral contreceptives.

Answer 52

Ethinyl group

Question 53

Non-oral contraceptives

Answer 53

Progestin Type –Injection * Depo-provera (methoxy progesterone) * Effective for three months –Implant * Norplant (levo norgestrel) * Effective for up to five years

Question 54

Effects of oocyte aging

Answer 54

* Increased incidence of **birth defects** * **​**Increased downs syndrome * Increased Klinefelters Syndrome * Increased incidence of **spontaneous abortion**

Question 55

What is the main cause of hirsutism?

Answer 55

Main cause is increased ovarian and/or adrenal androgen secretion \*Can be exacerbated by TeBG responses