Puberty and Menstrual Disorders 1 Flashcards
Hypothalamic-pituitary axis
- GnRH (from hypothalamus)
- stim LH and FSH (from ant pit- stored in gonadotrophs)
- stim estrogen and progesterone (from ovarian follicle)
Ovarian Cycle- phases
- Follicular phase- onset of menstruation to surge of LH
- Luteal phase- LH surge to first day of menses
dec estradiol and progesterone from the regressing corpus luteum- initiates
-inc in FSH- stim follicular growth and estradiol secretion
2 cell theory of ovarian follicular development
- LH stim Theca cells- produce androgens (androstenedione and T)
- FSH stim Granulosa cells- convert androgens into estrogens
Luteal phase
- LH and FSH are suppressed (neg feedback of elevated estradiol and progesterone)
- if conception doesnt occur- progesterone and estradiol dec due to corpus luteal regression- FSH rises!- follicular growth
GnRH
- stim syn and release of LH and FSH (from ant pit)
- estradiol enhances hypothalamic release of GnRH to induce the midcycle LH surge
ovarian cycle- estrogen
- early follicular development- estradiol is low
- 1 wk before ovulation- estradiol starts to inc- reaches a maximum 1 day b/f LH peak
- after LH peak- estradiol falls
- luteal phase- estradiol rises for 5-7 days after ovulation and then returns to baseline b/f menstruation
ovarian cycle- progestins
- follicular development- ovary secretes small amt of progesterone
- prior to ovulation, the grafian follicle begins to produce progesterone
- secretion of progesterone by corpus luteum reaches a max 5-7 days after ovulation- returns to baseline b/f menstruation
ovarian cycle- follicular development
- primordial follicles mature into a graafian follicle
- follicle ruptures- releases an ovum
- luteinization of ruptured follicle= corpus luteum
- 8-10 wks of fetal development- oocyte-granulosa cell complex= primordial follicle
- adult- graafian follicle
- granulosa cells adhere to ovum- cumulus oophorus- antrum forms along the granulosa cells- innermost layer forms corona radiata- corona radiata and oocyte is released at ovulation
ovarian cycle- ovulation
- LH surge causes ovulation
- stigma forms- ruptures the follicular basement membrane- oocyte is expelled
ovarian cycle- luteinization and corpus luteum fxn
- after ovulation- granulosa cells of rupture follicle undergo luteinization= forms corpus luteum
- corpus luteum produces progesterone!!
- if pregnancy doesnt occur, corpus luteum is replaced by a scar (corpus albicans)
overall cycle
- corpus luteum dies- E and P fall
- inc FSH
- follicles grow, secrete E
- E neg feedback on FSH
- dec FSH levels- causes selection of dominant follicle- produces high levels of E
- high E- positive feedback on LH
- LH surge- ovulation- corpus luteum produces high P
- high P, E- neg feedback on LH and FSH
Endometrium-2 zones
- outer portion (functionalis)- sloughed off at menstruation, contains spiral a’s
- inner portion (Basalis)- remains unchanged, basal a’s
Endometrial cycle- 3 stages
- menstrual
- proliferative (estrogenic)
- secretory (progestational)
Menstrual phase
- 1st day of menstruation- day 1
- sloughing of functionalis layer, compression of basalis layer
Proliferative phase
- endometrial growth due to estrogenic stim
- inc in spiral a’s, mitoses
Secretory phase
- after ovulation- progesterone secretion by corpus luteum stim glandular cells to secrete mucus, glycogen
- glands become tortuous and lumens dilated
- stroma is edematous
- spiral a’s
- endometrial lining- maximal thickness
Secretory phase- if no conception
- corpus luteum regress- dec progesterone- endometrium undergoes involution
- constriction of spiral a’s- ischemia of endometrium- necrosis- sloughing of endometrium
Secretory phase- coag pathway is necessary
- menstruation disrupts BVs- normal hemostasis allows for the to rapidly repair
- warfarin, aspirin, clopidogrel- heavy bleeding
Menarche- median age
- 12.43 yrs
- 2-3 yrs after thelarche, at Tanner stage IV
Primary amenorrhea
-no menstruation by 13 W/O secondary sexual development
OR
-age of 15 W/ secondary sexual development
normal cycle length
- 21-35 days long in adults
- irregular thruout adolescents