menstruation

Question 1

what causes estradiol levels to rise

Answer 1

presence of LH -> testosterone -> androstenedione -> FSH -> FSH receptors -> granulosa cells -> aromatase (FSH dependent) -> estradiol

Question 2

what causes the increase in LH levels around Day 11

Answer 2

estradiol, positive feedback with LH surge

Question 3

approximately when does luteinization occur

Answer 3

day 14
-granulosa cells become luteal cells -> led by estradiol -> make LH which makes progesterone

Question 4

why are progesterone levels so low until day 13? why do they drop around day 25

Answer 4

-dependent on luteinization, hasn’t occurred yet
-corpus luteum dies so progesterone dies off

Question 5

when do we see low estradiol levels

Answer 5

early follicular, menstrual, late luteal phase

Question 6

how does increase of estradiol affect AVPV nucleus

Answer 6

-regulates expression of kisspeptin in the AVPV
-estradiol always stimulates AVPV

Question 7

how does decrease of estradiol affect ARC nucleus

Answer 7

-regulates kisspeptin in the ARC
-estradiol always inhibits ARC

Question 8

how does ER (estrogen receptor) signaling differ between two populations of AVPV and ARC

Answer 8

-not known
-E2 receptors are the same in AVPV and ARC

Question 9

what do testicle havers have substantially

Answer 9

a sexually dimorphic nucleus

Question 10

what is the feedback loop for androgens

Answer 10

always negative

Question 11

what is the feedback loop for progesterone

Answer 11

always negative

Question 12

what is the feedback loop for inhibin

Answer 12

always negative for FSH only

Question 13

how does rapid rise of LH contribute to ovulation

Answer 13

changes in ovary and follicle

Question 14

what is the function of plasmin and collagenase

Answer 14

responsible for follicular wall thinning

Question 15

what is the function of prostaglandins

Answer 15

produced during pre-ovulatory gonadotropin surge = contraction of smooth muscle of ovary and constriction of blood vessels locally

Question 16

where are prostaglandins produced

Answer 16

in smooth muscle; theca externa which also produces prostaglandin receptors

Question 17

what occurs after ovulation

Answer 17

-granulosa cells invade antrum “luteal” cells
-corpus luteum will degenerate into corpus albicans if there is no pregnancy

Question 18

how will large quantities of luteal cells affect progesterone and estrogen

Answer 18

-generate lots of progesterone and estrogen (more LH receptors than FSH receptors on luteal cells)

Question 19

the endometrium thickens from day 7-15. why do we need the endometrium to thicken

Answer 19

where zygote can implant in endometrium, place to gestate

Question 20

what hormone rises during growing the endometrium

Answer 20

estradiol, grows endometrium

Question 21

why doesn’t the uterine lining continue to proliferate and thicken after day 14

Answer 21

increase of progesterone, inhibits estrogen which keeps endometrium in tact

Question 22

what hormone is released from day 13-27

Answer 22

progesterone

Question 23

what else can estradiol function as

Answer 23

-signals stromal cells to grow and divide
-epithelial cell phenotype becomes more columnar
-produces progesterone receptors

Question 24

what is progesterone’s purpose

Answer 24

-converting endometrium to a receptive state
-maintaining uterine thickness
-acts as an anti-proliferative in epithelial cells of uterus by blocking mitogenic mediators in cells via transcription factor and blocks estrogen receptors
-secretion of glycoproteins to promote implantation (L-selectin ligand: sLE)
-anti-apoptotic: tissue treated with progesterone significantly less apoptotic cells than tissue treated without progesterone

Question 25

what would happen to the cells of the endometrium if progesterone was blocked

Answer 25

would divide uncontrollably and die

Question 26

what happens to the corpus luteum toward the end of the menstrual cycle

Answer 26

-corpus luteum requires elevated LH signaling to survive
-no/little LH = atresia of luteal cells
-no luteal cells = no progesterone d

Question 27

what does having a drop of progesterone levels mean

Answer 27

-cell death
-endometrial inflammation
-extracellular matrix degradation
-menstruation