Menstrual Cycle Flashcards
The menstrual cycle is defined as a series of changes controlled by hormones from the _____ gland and _____ that help prepare the female ____ for possible pregnancy
Pituitary gland, ovaries, uterus
The first day of menstruation is considered Day ___ and Day ___ of the cycle.
28 and 1
How many stages are there in the menstrual cycle? What are they?
4
Follicular/proliferative stage, Ovulation, Secretory/Luteal phase, Menstruation
During the follicular/proliferative phase, the _____ produces FSH causing follicles (egg cell capsules) to form/mature. As the follicle grows, its cells produce ______ in increasing amounts.
pituitary
estrogen
Estrogen has (negative/positive) feedback on the pituitary FSH production.
Negative
_____ causes the uterine lining (endometrium) to grow thicker
Estrogen
Pituitary FSH causes several follicles in each ovary to mature at once, however, only 1 (typically) becomes the _____ follicle and ovulates
dominant
If >1 dominant follicle occurs, what can result?
Twins!
Ovarian follicles have several types of cells, what are they? Describe them.
Granulosa cells: several-cells-thick layer surrounding the egg and fluid around it
Cumulus cells: specialized layer of granulosa cells directly surrounding egg
Theca Cells: 2 thick layers of cells that surround the granulosa cells, outside of their basal lamina
____ and ____ cells make estrogen when stimulated by FSH to grow/divide
Theca and Granulosa
Once a follicle is clearly dominant, other follicles become _____ and _____
atretic and shrink
Typically, a dominant follicle must grow to at least _____ cm in diameter to ovulate
2.5 cm
All maturing follicles are secreting ______
estrogen (causes thickening of uterine lining)
During the follicular phase, estrogen is (inhibitory/stimulatory) to FSH and (inhibitory/stimulatory) to LH –> (negative/positive) feedback
Inhibitory; stimulatory
Positive feedback
Increased estrogen from the dominant follicle stimulates the ______ gland to produce _____; as Estrogen climbs rapidly, the dominant follicle gets big, and ____ production suddenly spikes/surges.
pituitary; LH; LH
What is the direct cause of ovulation?
LH surge
During ovulation, _____ potentiates GnRH and _____ inhibits FSH
Activin; Inhibin
Activin is made by ______ in the ______ phase and stimulates pituitary production of _____ –> (negative/positive) feedback
follicles; follicular; FSH; positive
Inhibin A: made in ______ phase, peaks at _______
Inhibin B: made in ______ phase and does a lot to inhibit _____
Follicular; ovulation
Luteal; FSH
During the Secretory/Luteal phase, the ruptured follicle heals inside the ovary, forming the _______ _______
corpus luteum (“yellow body”)
The corpus luteum produces _______
progesterone
The corpus luteum is necessary until _____ wks when the placenta is is making sufficient estrogen and progesterone
~8-11 wks
What does the estrogen/progesterone combo maintain during the secretory/luteal phase?
The added growth of uterine lining
If an ovulated egg is fertilized and a blastocyst implants,
_____ and _____ stabilize the corpus luteum and prevent it from decomposing, which maintains ______ levels
HCG and LH; progesterone
An embryo in the uterus will secrete _____
HCG
HCG mimics _____, maintaining the uterine lining just like ____ does
LH
The endometrium is not shed when _____ is present
HCG
What is the chemical that is detected by pregnancy tests?
HCG
If there is no blastocyst implantation, what occurs?
Menstruation
LH levels gradually (decrease/increase) after the LH surge
Decrease
On what day during the menstrual cycle does ovulation usually occur?
day 14
If embryo is not implanted by 14 days after ovulation, what will happen to the corpus luteum? Estrogen and progesterone levels?
corpus luteum decomposes
estrogen and progesterone levels decrease
With no progesterone to maintain the uterine lining, the _______ is shed and moves out through the vagina
endometrium
What is the hormonal event that is the direct trigger for menses to begin?
decrease in estrogen and PROGESTERONE levels
What is the structure that disintegrates in menses?
Corpus luteum, which leads to decrease in progesterone, which leads to endometrial shedding
What is the ovarian event that created the corpus luteum/endometrium?
Ovulation
What is the hormonal event that triggered the maturation of the ovarian follicles?
LH surge
What are FSH and LH levels typically like on the first day of a woman’s period?
Low
Are estrogen and progesterone levels high or low on the first day of menstruation?
Low
OCPs (decrease/increase) the hypothalamic release of GnRH and (decrease/increase) the pituitary release of LH and FSH
decrease; decrease (negative feedback!)
If a woman is taking an OCP and becomes pregnant, will she still have a period? Explain.
No; HCG from pregnancy prevent endometrial shedding, uterine lining will grow with estrogen, and she will not have a period
What are the effects of the decrease of pulsatile GnRH and decrease of LH on the ovaries?
No maturation of the follicles, no dominant follicle, no LH surge, no ovulation
What is happening to the uterus while a woman is taking a daily OCP?
The uterine lining will thicken due to progesterone
