Hormonal Cycle Flashcards
Ages of menarche and menopause
12.5
51
At birth females have 1 million primordial follicles. They oocytes are arrested in _______
prophase of the first meiotic division until menarche
The hypothalamus secretes ________ from the _________ in a ________ manner.
GnRH from the arcuate nucleus in a pulsatile manner (every 70-90 minutes)
GnRH stimulates the ________ to release ________
anterior pituitary to release FHS and LH (gonadotropins)
TSH acts at
thyroid gland
released from ant pit
ACTH acts at
adrenal cortex
released from ant pit
TSH and LH act at
testes and ovaries
released from ant pit
GH acts at
entire body
released from ant pit
PRL (prolactin) acts at
mammary glands
released from ant pit
endorphins act on
pain receptors in brain
released from ant pit
LH stimulates ______, which causes _________
- LH stimulates theca cells of ovary to produce androgens
2. Androgens to to granulosa cell of ovary and are converted to estrogen by aromatase
FSH stimulates _______ which causes ________
- FSH stimulates granulosa cells to convert androgens (coming from the thecal cells) to estrogen by aromatase during the follicular phase of the menstrual cycle
Estradiol (estrogen) has a negative feedback on ______ and a positive feedback on ______
negative fb on GnRH and FSH/LH most of the cycle, but a positive fb on GnRH/FSH/LH for days 12-14 (high estrogen levels during this time)
So basically granulosa cells of ovary produce ______ and theca cells produce _______
estradiol
androgen
Estrogen provides _________ to hypothalamus and anterior pituitary for most of the cycle, but ________ for days 12-14
negative fb for most
positive fb for days 12-14
the positive fb of estrogen is mostly acting on LH
In order for FSH and LH to be released, you need ________
a PULSATILE release of GnRH
LH acts on 2 places in the ovary (and why)
- growing follicle (for ovulation and to produce estrogen, this mid-cycle increase of estrogen will stimulate more LH secretion, positive FB)
- corpus luteum (which secretes progesterone and estrogen after ovulation to inhibit FSH and LH secretion)
Phases of menstrual cycle
follicular phase, ovulation, luteal phase
Day 1 of follicular phase:
- First day of bleeding
- progesterone withdrawal is happening (causes period bleeding)
- Prostaglandins are released–> causes contractions of uterus
- -> ischemic pain (cramping)
- hormones are all at their LOWEST points on day 1
- this causes at DECREASE in the negative feedback, resulting in FSH production
FSH production on day 1 of follicular phase causes
- new follicles to mature
- dominant follicle to be selected
- granulosa cells increase and secrete estradiol
Follicular phase- Estradiol acts at the LH receptors on
theca cells, cause androgen secretion, which are converted to more estradiol by aromatase
Follicular phase- Rising estradiol causes an INCREASE in negative feedback at the hypothalamus, which will _______
decrease FSH and increase LH
Determining Dominant Follicle- FSH binds to receptors on the granulosa cells, causing ______
proliferation of cells –> more binding of FSH –> more estradiol produced
Determining Dominant Follicle- The follicle with the ________ becomes the dominant follicle, and then OVULATION HAPPENS!
greatest # of granolas cells
this is the best follicle- has the most estrogen production, greatest number of granulosa cells
The ONLY FOLLICLE that ovulates is _________
the dominant follicle
Ovulation- estradiol produced causes
a positive feedback at hypothalamus causing an increase in LH
_________ happens around days 11-13 of cycle
LH Surge
Ovulation starts ______ AFTER the LH surge
30-36 hours
-so ovulation happens around day 14 of cycle
During ovulation what physically happen to oocyte?
oocyte is expelled from follicle into fallopian tube, and the follicle becomes the corpus luteum (follicle without egg in it anymore is corpus luteum)
Luteal phase of menstrual cycle is ________ dominant
progesterone dominant (bc the progesterone is coming from the corpus luteum)
Luteal phase- Maximum production of progesterone happens _________
3-4 days after ovulation (and lasts 11 days)
Luteal phase- If there is NO implantation, _______
involution of the corpus lute occurs (takes 13-14 days), and there is a DECREASE in progesterone
(decrease in progesterone, no negative fb, this increases FSH and LH, start producing estradiol, get your period)
Luteal phase- if there IS implantation, _________
hCG is secreted from corpus luteum, this maintains the CL and there is CONTINUED progesterone secretion
(progesterone prevents your period)
During the Luteal phase, progesterone provides __________
a NEGATIVE feedback for FSH and LH
Timeline if follicular phase
CAN VARY
overall cycle is about 28 days
Timeline of luteal phase
ALWAYS 14 DAYS!!!
What causes ovulation?
LH surge
What causes follicle growth?
estradiol
What causes estradiol to increase?
FSH
Negative fb from estradiol causes
decline in FSH
What forms during ovulation?
corpus luteum
When progesterone stops being produced, what happens?
withdrawal phase- menses
During menstruation, endometrium is __________
sloghed to basal level (bleeding happens bc progesterone withdrawal)
- compact stroma cells
- short, narrow endometrial glands
During the follicular phase, what happens to endometrium?
- Estrogen causes growth of the endometrium
- stroma thickens
- glands elongate and are straight/tubular
- endometrium is proliferative and growing
What progesterone is released during luteal phase, what happens to endometrium?
- Differentiation
- Stroma becomes loose and edematous
- blood vessels twist and thicken (spiral arterioles)
- glands become tortuous
- it’s called a “secretory endometrium” and it’s getting ready to support a pregnancy
How does Estradiol alter the endocervix and cervical mucus?
- causes sperm capture, storage and transport
- thin
- clear
- water
- conducive to preparing for pregnancy
How does Progesterone alter the endocervix and cervical mucus?
- thick (prevents sperm)
- opaque
- tenacious
- conducive to
How does progesterone affect the breasts?
- stimulates acinar glands
- rounds them
- increased tenderness
How does progesterone affect body temperature?
increases body temp by
0.6-1 degree F
Leuoprolide
- acts at hypothalamus
- hormonal control
- takes 2 weeks to decrease FSH/LH
- GnRH agonist
- when continuous, decreases pulsate GnRH release
- decrease initial surge of FSH/LH-can only use for 3-6 months, puts pt into “early menopause”
Ganirelix
- acts at hypothalamus
- immediately decreases FSH/LH
- GnRH antagonist
Clomiphene citrate
- acts at hypothalamus
- Causes ovulation
- can make someone ovulate, for someone with PCOS who is ovulating irregularly- can have multiple dominant follicles, twins/triplets
- Antagonist of estrogen at hypothalamus
- Increases LH/FSH release
Combination oral contraceptives
*acts at ovary
-Progestin: suppression of LH secretion= no ovulation
-Thicken cervical mucus
and altered fallopian tube peristalsis
-Estrogen: suppression of FHS secretion= no dominant follicle (won’t be able to ovulate)
Progestins
- acts at ovary
- Depo-Provera
- Nexplanon
- Thicken cervical mucus
- Alters endometrial proliferation (“hostile” environment)
- Some suppress ovulation (if high enough dose)
