normal menstruation and menstrual cycle Flashcards
how long is luteal phase of the menstrual cycle?
- constant duration of 14 days
- follicular phase varies from 10-16
what does inhibin do?
selectively inhibits FSH at anterior pituitary
what are the 3 events that occur during menstrual cycle?
- follicular phase, ovulation and luteal phase
what hormone levels rise in the first days of the follicular phase (first few days of menstrual cycle)
- FSH
within the follicle, there are 2 types of cells involved in oestrogen and progesterone synthesis, what are these cells?
- theca and granulosa cells
theca cells respond to what hormone?
- LH
granulosa cells respond to what hormone
- FSH
LH stimulates production of what from theca cells?
androgens from cholesterol - which are converted to oestrogen by aromatisation in granulosa cells under influence of FSH
as follicles grow, there is negative feedback by what 2 hormones on pituitary to decrease FSH secretion?
- oestrogen and inhibin
the decrease in FSH secretion allows for the selection of one follicle to continue its development towards ovulation. what is this follicle called?
- dominant follicle
the dominant follicle continues to secrete what 2 hormones?
- oestrogen and inhibin which enhances androgen synthesis under LH control
inhibin and activin has opposite actions true or false?
- true activin (also produced by granulosa cells) and pituitary works to increase FSH binding in follicles
other regulators produced by the theca cells include?
- IGF-1
- IGF-2
-> produced under action of LH and receptors are present on both theca and granulosa cells
what marks end of follicular phase and start of ovulation?
- dominant follicle has grown and matured
production of oestrogen increases until it reaches threshold to exert a [ ] feedback effort on hypothalamus and pituitary to cause the LH surge
- positive
granulosa cells surround the [ ], forming structures called [ ]
- oocytes
- follicles
follicles go through 4 key stages of development in the ovaries what are these?
- primordial follicles
- primary follicles
- secondary follicles
- antral follicles aka graafian follicles
once follicles reach the secondary follicle phase they develop receptors for [ ]
- FSH
-> further development after secondary follicle stage requires stimulation from FSH
as follicles grow, the granulosa cells that surround secondary follicles secrete increasing amounts of [ ]
- oestradiol (oestrogen)
oestrogen has a [ ] feedback effect on pituitary gland
- negative
-> reducing the quantity of LH and FSH produced
-> rising oestrogen, causes cervical mucus to become more permeable -> so sperm can penetrate cervix around time of ovulation
one of the follicles will develop further and become the [ ]
dominant follicle
what hormone spikes just before ovulation
- LH
-> causing dominant follicle to release the ovum (unfertilised egg) from the ovary
ovulation occurs when?
- 14 days before end of menstrual cycle
after ovulation, follicle that released ovum collapses and becomes what?
- corpus luteum
corpus luteum secretes progesterone which maintains what?
- endometrial lining
progesterone also causes cervical mucus to do what?
- become thick and no longer penetrable
- also secretes small amount of oestrogen
when fertilisation occurs, what structure of the embryo secretes HCG?
- syncytiotrophoblast
HCG maintains what?
- corpus luteum
- without HCG corpus luteum degenerates
- this is what pregnancy tests check for to confirm pregnancy
if no fertilisation, what happens to corpus luteum?
- degenerates and stops producing oestrogen and progesterone (corpus luteum is remaining granulosa and theca cells)
- causing endometrium to break down and menstruation to occur
stromal cells of endometrium does what in response to menstruation?
- release prostaglandins
- prostaglandins encourage the endometrium to break down and uterus to contract
when does menstruation begin?
- starts on day 1 of menstrual cycle
- negative feedback from oestrogen and progesterone on hypothalamus and pituitary gland ceases, allowing LH and FSH to rise again, and cycle to restart
menstruation involves what layers of endometrium to break down?
- superficial and middle layer separating from basal layer
study this diagram
theca granulosa cells around follicles secrete what?
- oestrogen
oestrogen has a negative feedback effect on hypothalamus and ant pituitary suppressing release of { }, { }, and { }
- GnRH, LH and FSH
oestrogen is what?
- steroid sex hormone
- produced by ovaries in response to LH and FSH
the most prevalent and active version of oestrogen is what?
- 17-beta oestradiol
- acts on tissues with oestrogen receptors to promote female secondary sexual characteristics
what does oestradiol stimulate?
- breast tissue development
- growth and development of female sex organs - vulva, vagina and uterus at puberty
- blood vessel development in uterus
- development of endometrium
progesterone is what?
- steroid sex hormone produced by corpus luteum after ovulation
- when pregnancy occurs, progesterone is produced mainly by placenta from 10 weeks gestation onwards
progesterone acts on tissue previously stimulated by oestrogen. what does it act to do?
- thicken and maintain the endometrium
- thicken cervical mucus
- increase body temperature
LH surge is best predictor of WHAT?
- imminent ovulation and is used in ovulation predictor tests
- ovulation occurs around 12 hrs after LH surge - when dom follicle ruptures and releases oocyte
the high levels of progesterone during luteal phase (by LH) suppress FSH and LH secretion to a level that will not produce what?
- further follicular growth in the ovary during that cycle
during proliferative phase, during follicular phase what happens to endometrium?
- endometrium changes from single layer columnar cells to a pseudostratified epithelium w frequent mitoses
if fertilisation occurs, progesterone induces formation of a temporary layer called the?
decidua
what is amenorrhea?
- absence of menstruation > 6 months
what is oligomenorrhea?
- periods at intervals of > 35 days or 5 or fewer menstrual cycles over a year
what is menorrhagia?
- prolonged and increased > 80ml per period menstrual flow
- heavy menstrual bleeding
causes of menorrhagia?
- fibroids
- adenomyosis
- endocerivcal/endometrial polyp
- endometrial hyperplasia
- IUCD
- PID
- PID
- endometriosis
- malignancy of uterine or cervix
- hormone producing ovarian tumours
- AV malformation
- drugs - anticoags - warfarin, clopidogrel, rivaroxaban
what is climateric?
- perioid around beginning of menopause also called perimenopause
- marks transition from reproductive state to non-reproductive state
premature menopause is menopause occurs before age of?
- age of 45
- 2 measurements are done to confirm this
due to cessation of follicular development and ripening, levels of various hormones decrease. which ones are these?
- oestradiol, progesterone, inhibin, androgens
physical effects of menopause?
- vasomotor symptoms - hot flushes and night sweats
- joint aches and pains
- dry and itchy skin
- hair changes
- vaginal dryness and soreness causing dyspareunia
- recurrent UTI, urinary urgency
- urogenital prolapse
- osteoporosis increasing risk of fractures
- CV disease
- dementia
psychological effects of menopause?
- labile mood, anxiety, tearfulness
- loss of concentration, poor memory
- loss of libido
medical mx for menopause?
- HRT - main hormone is oestrogen
- progesterone
- testosterone
cyclical combined HRT is often recommended for who?
- perimenopausal women who still get periods and involves taking oestradiol tablet each day of month and progestogen tablet on last 14 days
- important to note women on continous combined systemic HRT can often have erratic bleeding first 3-6 months after therapy
tx for reduced libido is?
testosterone
what SSRIs are being used as non-hormonal tx of menopausal symptoms often in women w history of breast cancer but HRT still remains far more effective
- fluoxetine
contraception should continue for how many years are last period in women under 50 and over 50?
- 2 years in women <50
- 1 year in women >50
side effects of HRT
- oestrogen related - breast enlargement, leg cramps, dyspepsia, fluid retention, nausea, headaches
- wear off w time
side effects of progestogen?
- similar to premenstrual symptoms
- fluid retention, breast tenderness, headaches, acne, mood swings, depression, irritability, constipation, increased appetitie
is HRT CI in breast cancer?
- yes
- also endometrial cancer
- known VTE
- suspected pregnancy
- acute liver disease
- thrombophilia etc
what are some relative CI to HRT?
- uninvestigated abnormal bleeding
- large uterine fibroids
- past hx of benign breast disease
- unconfirmed personal hx or strong FH of VTE
- chronic stable liver disease
- migraine w aura
