Physiology of Female Reproductive System Flashcards Preview

SF3-EXAM 4 (CAMELITA) > Physiology of Female Reproductive System > Flashcards

Flashcards in Physiology of Female Reproductive System Deck (55)
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1

Follicular structures

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

2

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

Theca interna

3

Progesterone is made from which cells?

Granulosa lutein cells

4

When is the corpus luteum formed?

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.

5

What are the two phases of follicular growth?

  • 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

 

6

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

  • 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

7

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

  • 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

8

Aromatase is an important enzyme in ______ synthesis.

Estrogen

9

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

Androgens because we stop converting androgens to estrogens. 

 

10

Ovarian steroid synthesis

11

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

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. 

12

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

Estrone and testosterone

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

-OR-

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

13

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

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

14

What is the role of SF1?

SF1 is a nuclear receptor that stimulates StAR in mitochondria membrane

15

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

LRH-1

16

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

Stigmata

17

What events take place right before ovulation?

  • 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.

18

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

Oxytocin

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

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 _________.

Corpus luteum

20

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

  • Collagenase
  • Plasmin

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

21

What are the 3 phases of corpus luteum development?

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

NOTE: FSH has no direct role in corpus luteum maintenance

22

What occurs during the early luteal phase?

  • 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

23

What occurs during the advanced luteal phase?

  • 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

24

What occurs during the late luteal phase?

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

25

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

Follicular phase

  • Granulosa cells stimulated by FSH

Luteal phase

  • Granulosa cells stimulated by LH

26

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

Sertoli; granulosa

27

Inhibin

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

 

28

Activin ________ (stimulates/inhibits) FSH secretion.

Stimulates

29

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

Activin

30

Which estrogen type has the most estrogenic activity?

E2- 17 betaestradiol