Female Reproductive Cycle

MENSTRUAL cycle: Day 0 of 1st cycle = Day 28 of 2nd cycle

FOLLICULAR phase in OVARIAN cycle:
1.ANT PITUITARY GLAND secretes FSH and LH, follicular cells slowing forming.

2. GRANULOSA cells secrete ESTROGEN; THECA cells secrete androstenedione and converted to estrogen by granulosa.

3. High estrogen level act as NEGATIVE feedback and suppress secretion of FSH and LH, thus we see a "dip" near 2/3 of the phase

4.Granulosa cell also secretes INHIBIN, which inhibit FSH secretion

5.However, later on Super High estrogen secreted by granulosa cells in turn act as POSITIVE feedback and thus the hormone "FSH and LH" increase again.  FSH is up a little as it is still inhibited by inhibin. LH is back high up until a level which its called LH SURGE, and this is when the ovum released during OVULATION (DAY 14).

PROLIFERATIVE phase of UTERINE cycle, ESTROGEN is the one that induce production of NEW ENDOMETRIAL layer.

after ovulation, LUTEAL phase of ovarian cycle:
high FSH and LH induce follicle into CORPUS LUTEUM (yellow body)


CORPUS LUTEUM still produces PROGESTERONE and estrogen but estrogen is not the primary product thus there is a "dip".

THERE IS A CHANCE FOR THE EGG TO GET FERTILISED, THUS MUST PREPARE ENDOMETRIUM FOR IMPLANTATION.

PRO-GEST-ERONE
(FOR GESTATION= FOR PREGNANCY)

SECRETORY phase of UTERINE cycle:
PROGESTERONE:
Increase blood flow to endometrial by stimulationg development of SPIRAL ARTERIES, allow embryo to have good access to nutrient


Induce SECRETION from uterine GLANDS, for nourishment

REDUCE CONTRACTILITY of uterine MUSCLES

LITTLE ESTROGEN + LOTS PROGESTERONE prepare endometrium for pregnancy.

Also, they suppress FSH and LH, so they are LOW in LUTEAL PHASE

corpus luteum also produce INHIBIN that suppress FSH and LH

corpus luteum needs FSH and LH to SURVIVE, thus it becomes ATROPHY

when it ATROPHY, ESTROGEN & PROGESTERONE DROPS!

MENSTRUATION occurs, endometrial lining starts to SHED. (AVERAGE: 40ml)

AND FSH LH BACK UP AGAIN, as low estrogen and progesterone. START OF NEW CYCLE!

IF PREGNANCY OCCURS,
when Blastocyst implanted, embryo start to produce HCG, which structurally similar to LH, and enough to keep corpus luteum ALIVE.

ALIVE CP continue to produce ESTROGEN and PROGESTERONE to maintain pregnancy.
(first 2-3mths only)

PLACENTA then take over production of progesterone.

PREGNANCY TEST:
CHECK HCG