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Flashcards in Endocrinology of OBGYN Deck (46)
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1
Q

what are the two phases of the ovarian cycle? when does each begin?

A

follicular - begins day 1

luteal - begins after ovulation

2
Q

what are the features of the follicular phase

  • what forms / develops
  • what happens to the endometrium
  • what follows?
A
  • follicle development
  • endometrial proliferation
  • follicular phase is followed by ovulation
3
Q

what are the features of the luteal phase?

  • what forms / develops
  • what happens to the endometrium
  • what follows?
A
  • corpus luteum forms
  • endometrial differentiation
  • followed by menses
4
Q

when does FSH rise in the ovarian cycle?

A

early in follicular phase, and also at ovulation

5
Q

what is the role of estrogen during the follicular phase on the anterior pituitary?

A

negative feedback

6
Q

what is the role of estrogen during mid-cycle on the anterior pituitary?

A

36 hours of relatively high estrogen concentrations exert positive feedback at the level of the anterior pituitary

7
Q

what is the role of estrogen (and progesterone) during the luteal phase on the anterior pituitary?

A

negative feedback

8
Q

when does inhibin A rise? what is its role?

A

luteal phase

negative feedback

9
Q

the inhibins are synthesized by what cells of the ovary?

A

granulosa cells

10
Q

what is an important role of inhibin B

A

regulation of FSH

11
Q

follicular phase is associated with what hormone?

A

estrogen

12
Q

theca cells synthesize androstenedione in response to what hormone?

A

LH

13
Q

where is androstenedione converted to estradiol? what regulates this process?

A

granulosa cells

FSH regulates this conversion

14
Q

follicular phase has a role for what two hormones?

A

FSH and LH

15
Q

early to mid follicular phase - what is estrogen doing?

A

applying negative feedback on HPG axis

16
Q

why does estrogen continue to rise during the follicular phase despite negative feedback on LH and FSH?

A

presence of more theca cells, and more secretions from those theca cells

also increased sensitivity, so more steroid production

17
Q

at day 14, what induces ovulation? what is absolutely required?

A

surge in LH and FSH

LH is absolutely required

18
Q

what hormone is responsible for the rise in basal body temperature during ovulation?

A

progesterone

19
Q

the corpus luteum forms from what cell types?

A
thecal 
granulosa 
fibroblast 
endothelial 
immune cells 
lipids
20
Q

when does the corpus luteum reach maturity?

A

7-8 days following ovulation

21
Q

what is the change in the regulation from the follicular phse to the luteal phase?

A

LH becomes key regulator in the luteal phase - theca cells become more responsive to LH

22
Q

what is the key difference in granulosa cells during the luteal phase?

A
  • LH now regulates
  • progesterone synthesis is now occurring
  • increased in uptake of cholesterol
23
Q

during the luteal phase, what hormone regulated the differentiation and secretory development of uterine endometrium?

A

progesterone

24
Q

what are the key endometrial changes 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
25
Q

what allows for the ovarian cycle to reset?

A
  • regression of corpus luteum - decline in steroid cynthesis
  • decrease in negative feedback on anteior pituitary (concentrations of LH and FSH rise)
26
Q

what are the steps of implantation?

A
  1. hatching
  2. apposition
  3. adhesion
  4. invasion
27
Q

what constitutes ‘hatching’ during implantation and formation of the palcenta?

A

breakdown of zona pellucida

28
Q

what constitutes ‘apposition’ during implantation and formation of the placenta?

A

trophoblastic cells of the blastocyst make contact with endometrium

29
Q

what constitutes ‘adhesion’ during implantation and formation of the placenta? what mediates this process?

A

integrin mediated attachment between trophoblast and stromal cells (decidual cells) of the endometrium

30
Q

what constitutes ‘invasion’ during implantation and formation of the placenta?

A
  • trophoblast differentiates into cytotrophoblast and syncitiotrophoblast
  • syncitiotrophoblasts send out protrusions and invade endometerium
31
Q

what are the steps of placenta formation?

A
  1. invading syncitiotrophoblast breaks through maternal veins and arteries
  2. allows for pools of maternal blood to interface with syncytiotrophoblasts
  3. primary chorionic villi form
  4. within villi, capillaries form
32
Q

what are the components of the fetal placenta?

A
  • syncytiotrophoblasts
  • cytotrophoblasts
  • mesenchyme
  • fetal blood vessels
33
Q

what is contained in the intervillous space?

A

blood trapped between fetal villous and maternal endometrium

34
Q

what are the components of the maternal placenta?

A
  • decidual cells

- maternal arteries and veins

35
Q

what happens to the corpus luteum upon implantation?

A
  • placental derived hCG stimulates ovarian steroidogenesis

- secretes relaxin to inhibit myometrial contractions

36
Q

after week 8 following implantation, maintenance of pregnancy is dependent upon what hormones? what are their roles?

A

progesterone - suppress uterine contractions, inhibit PG production, impact immune response

estrogen - stimulate uterine growth, thicken vaginal epithelium, growth, and development of mammary epithelium

37
Q

what are the physiological roles of hCG? where does it bind?

A
  • bind LH receptors
  • maintain corpus luteum
  • maintain ovarian steroid production needed for first 7-8 weeks of gestation
38
Q

where is hCG produced? when is it secreted? when does it peak?

A
  • syncytiotrophoblast (fetal placenta-derived)
  • secreted around week 6 of pregnancy
  • increases throughout pregnancy
39
Q

what are the physiological roles of human placental lactogen (hPL)?

A
  • fetal metabolism
  • fetal growth and development
  • stimulates production of IGF, insulin, adrenocortical hormones, surfactant
40
Q

where is hPL produced? when is it secreted? when does it peak?

A
  • syncytiotrophoblast
  • secreted around week 6 of pregnancy
  • increases throughout pregnancy
41
Q

what are the physiological roles of CRH?

A
  • onset of labor
  • production of PGs
  • maintain blood flow in placenta
42
Q

where is CRH produced? when does it peak?

A
  • syncytiotrophoblast and trophoblast

- increases throughout pregnancy and peaks during labor

43
Q

what are the physiological roles of progesterone and 17-hydroxyprogesterone?

A
  • inhibit PG production
  • suppress uterine contractions
  • modulate immune response
44
Q

where is progesterone produced during pregnancy? what is required for its production?

A
  • first 8 weeks, produced by corpus luteum under control of hCG
  • after 8 weeks, produced by syncytiorophoblast
  • requires use of maternal LDL
45
Q

what are the physiological roles of DHEA?

A

substrates for estrogen synthesis

46
Q

where is DHEA produced?

A
  • maternal adrenal gland
  • fetal adrenal gland
  • fetal liver