Exam #4: Female Reproductive Physiology II Flashcards Preview

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Flashcards in Exam #4: Female Reproductive Physiology II Deck (33)
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1
Q

Outline steroidal production during the follicular phase. What regulates the production of steroidal hormones during this phase?

A
  • Theca (that surround the follicle with granulosa cells) cells synthesize androstenedione in response to LH
  • Androstenedione is converted to estradiol in granulosa cells (enzymes), which is controlled by FSH

*****IT takes BOTH cells, theca & granulosa to make estradiol & BOTH FSH & LH

2
Q

What is the effect of estrogen production during the follicular phase?

A
  • Negative feedback on the hypothalamus & anterior pituitary (primarily) to keep the levels of LH & FSH relatively low
  • Estrogen also causes proliferation of the endometrium
3
Q

What is the effect of the rise in FSH in mid-follicular phase?

A

1) Development of the granulosa and theca cells
2) Increase in steroid production
3) Extremely rapid follicle growth

4
Q

What is the difference between the theca externa and theca interna cells?

A

Theca externa= capsule of the follicle

Theca interna= hormone producing

5
Q

In the follicular phase, how many mature follicles actually become ready for ovulation?

A

Only one dominant or mature follicle actually becomes ready for ovulation, the rest undergo atresia

6
Q

What causes the atresia of the non-dominant follicles?

A

Decline in FSH that may be induced by Inhibin B

*****This is how we get just one follicle for ovulation

7
Q

What happens during the follicular phase in regards to the endometrium?

A

Prolifeation of the uterine endometrium

  • stromal cells
  • growth of endometrial glands
  • blood vessel development
  • mucus secretion

*Note that this is regulated by estrogen

8
Q

When does estrogen peak?

A

Just before day 14 i.e. just before ovulation

9
Q

What is the effect of the estrogen peak?

A

Positive feedback on HPG axis, which results in a surge of gonadotropin or LH/ FSH

10
Q

When is there a peak of LH & FSH? What happens?

A
  • Day 14

- Ovulation i.e. rupture of the follicle & release of the oocyte

11
Q

What is absolutely required for ovulation?

A

LH surge at Day 14

NO LH = NO ovulation

12
Q

What happens to progesterone levels after ovulation?

A

Rise i.e. progesterone levels rise in the Luteal Phase

13
Q

What effect does progesterone have on basal body temperature?

A

Increase in basal body temp

**Thus, basal body temperature can be a marker ovulation

14
Q

What are basal body temperature measurements used for?

A

Determining if ovulation has occurred i.e. increased basal body temperature is indicative that ovulation has occurred

15
Q

What is the corpus luteum?

A

A temporary endocrine gland that secretes estradiol and progesterone; this the remnant of the rupture follicle
- Luteum= lipid i.e. cholesterol for steroid production

16
Q

When does the CL reach a mature state?

A

7-8 days following ovulation

17
Q

What happens to steroidal production during the luteal phase?

A

Production of BOTH estradiol and progesterone

  • LH binds theca-lutein cells & stimulates andostenedione formation
  • Androstenedione is again converted to estradiol in the lutenized granulosa cells
  • Additionally, there is an upregulation of the genes necessary to make progesterone in the lutenized-granulosa cells

Thus, BOTH the theca & granulosa cells respond to LH

18
Q

What changes are seen in granulosa cells that helps them form progesterone?

A
  • Upregulation of LDL receptors for cholesterol
  • Enzymes necessary to form progesterone from cholesterol
  • LH receptors on granulosa cells
19
Q

What happens to the endometrial lining during the Luteal Phase?

A

Differentiation and secretory development that is regulated by PROGESTERONE

*This is the SECRETORY phase that gets ready for implantation

20
Q

What are the key endometrial changes that occur during the luteal phase?

A
  • Increased complexity of vascular and glandular structures
  • Accumulation of substances in glands
  • Deposition of lipids and glycogen in stromal cells
  • Increased blood supply
21
Q

Describe the feedback mechanisms of the Luteal Phase.

A
  • Progesterone & inhibin A exert a negative feedback at the level of the ANTERIOR PITUITARY

*****Gonadotropin production declines & results in a decline in steroid production

22
Q

When does the CL begin to regress? What does it become?

A
  • 26th day

- Corpus albicans

23
Q

What does the decline in estrogen & progesterone production of the Luteal Phase result in?

A
  • Release of proteolytic enzymes that cause tissue lysis
  • Increase in prostaglandin production that increases myometrial contraction

Note that progesterone normally INHIBITS these actions i.e. prostaglandins

24
Q

What causes the menstrual cycle to restart again?

A

Low steroid levels relieve the negative inhibition on the HPG axis & gonadotropin production begins to rise again

25
Q

If fertilization occurs, what allows invasion into the endometrium?

A

The blastocyst expresses multiple enzymes that allow invasion

26
Q

How is steroid production maintained if there is fertilization?

A

If IMPLANTATION occurs, CL does NOT regress

- hCG stimulates ovarian steroidogenesis

27
Q

What receptors does hCG bind to?

A

LH receptors; thus, hCG mimincs LH to maintain steroidogenesis & CL is maintained

28
Q

When is there a transition in the dependence of the CL for steroids and the placenta?

A

8 weeks

29
Q

Draw the relative concentrations of the gonadotropins during the menstrual cycle.

A

N/A

30
Q

Draw the relative concentrations of the steroid hormones during the menstrual cycle.

A

N/A

31
Q

What are the age related changes in hormone release that occur in puberty?

A

1) Low amplitude nocturnal pulses of gonadotropin release

2) Increased steroid production in response, which causes a number of physiological changes

32
Q

What is menarche indicative of hormonally?

A

Estrogen-mediated endometrial growth

33
Q

What age related hormonal changes occur in menopasue?

A

1) ~36 y/o loss of ovarian follicular activity
2) Decline in estradiol & inhibin
3) Results in a loss of negative feedback and upregulation of LH & FSH

*****There is a marked overall decline in estrogen production that leads to the negative effects of menopause

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