The Female Cycle

1st powerpoint

most of interactions in female reproductive cycle (hormones and tissues) are based on…

negative feedback systems

where does the process of hormones start?

in the brain with signaling hormones (secreted by hypothalamus that stimulate anterior pituitary)

what do hormones from the anterior pituitary gland control?

the ovarian cycle

what do the ovaries, in turn, secrete?

hormones that control the uterine cycle

what is the “control center” of the endocrine system?

hypothalamus

what does the hypothalamus do?

• monitors chemical and neural signals from the body

  • controls appetite

• controls release of hormones to maintain homeostasis.

  • body temp (vasodilation/ vasoconstriction)

  • sweating and shivering

  • respiratory rate

what is the hypothalamus apart of/ where is it located?

• part of diencephalon

• located just inferior to thalamus (hypo= below; hypothalamus)

• superior to pituitary gland

hypothalamus communicates with the…… via the…

anterior pituitary gland via the hypophyseal portal system

what is the hypophyseal portal system?

blood vessels that communicate between hypothalamus & anterior pituitary gland.

list steps of hypophyseal portal system:

1. hypothalamus hormones —> capillary bed of hypophyseal artery

2. blood with hormones —> hypophyseal portal system

3. hormones in portal system —> anterior pituitary

4. A.P. secretes its own hormones into the A.P. capillaries

5. these then empty into the systemic bloodstream.

what hormones do not enter the systemic blood circulation?

hypothalamic hormones

• goes to pituitary gland which then release their hormones into blood circulation.

what does the anterior pituitary gland respond to and how does it respond?

responds to GnRH (from hypothalamus)
responds by secreting hormones that stimulate the ovaries (FSH and LH)

what is the anterior pituitary gland composed of?

glandular tissue

where is the pituitary gland located?

sits in sella turcica of sphenoid bone

what hormones does the anterior pituitary gland secrete?

• gonadotropic hormones

  • FSH

  • LH

• TSH (thyroid stimulating hormone)

• Prolactin

what hormone does the hypothalamus secrete?

GnRH

what structure does GnRH target?

anterior pituitary

what does the anterior pituitary do in response to GnRH?

release FSH and LH

what do the gonadotropin hormones do (in general)?

stimulate gonads

• gamete production

• sex hormone secretion

what are the target cells of FSH?

ovarian follicles

target cells of LH?

ovarian follicles and corpus luteum

what is GnRH? (simple, one word answer)

neurohormone

how in GnRH secreted?

in pulsations- change frequency/ amplitude in different parts of cycle

• early follicular phase- 1/90 min

• late follicular/ ovulatory phase- 1/60-70 min

• secretory phase- less frequent but higher in amplitude

what does the inhibition of FSH trigger?

LH surge

what does FSH do?

promotes follicle development in ovary

causes maturation of oocyte, corona radiata, and development of follicular antrum

what occurs as estrogen levels rise?

GnRH is inhibited

this leads to the fall of FSH and triggering of LH surge

What does LH do?

triggers ovulation and formation of corpus luteum

what are estrogen and progesterone secreted by?

the ovaries

what are estrogens?

class of hormones associated with female characteristics

• cholesterol based steroid hormones

what is estradiol?

principle estrogen responsible for female sex characteristics and maturation of sex organs

where does estradiol come from?

developing follicles

adrenal cortex

placenta

what is estradiol important for?

bone health

what does estradiol (excess estrogen/ estradiol) contribute to?

endometriosis

fibroids

breast, ovarian, and endometrial cancer

what is estriol?

only produced during pregnancy and secreted by placenta

• Aimee has estriol!

what is estrone?

only estrogen that remains in significant amounts after menopause (widely found in body)

• Erin is closest to having estrone!

what is estrogen (mainly estradiol) secreted by?

the ovarian follicles that respond to FSH and mature

• causes endometrium to develop a new functional layer

what is Progesterone secreted by?

corpus luteum after ovulation

• only if fertilization occurs

how do you know if it is an ovulatory/ corpus luteal cyst?

with color, shows ring of fire

what does progesterone do?

• prepares and maintains body for pregnancy

• inhibits uterine irritability (tendency to contract)

• blocks development of new ovarian follicles

• causes formation of cervical mucous plug during pregnancy (protect against infection)

• inhibits maternal immune system (prevents rejection of embryo)

• stimulates growth of uterine wall and uterine blood vessels to support pregnancy

estrogen and progesterone have what kind of feedback?

negative feedback

reduces production

• GnRH

• LH

• FSH

what are the phases of the menstrual cycle WITH days (7phases)?

• menstrual phase: days 1-5

• early mid proliferative phase: days 6-10

• late proliferative phase: days 11-12

• ovulatory phase: days 13-14

• secretory phase: days 15-22

• late secretory phase: days 23-25

• late secretory phase: days 26-28

what happens to hormones during menstrual phase?

• GnRH—pulsations increase

• FSH—begins to rise

• LH—low levels also secreted

• Estrogen—low

• Progesterone--low

what happens to ovaries during menstrual phase?

• Early follicular phase- Follicles begin to respond to FSH

• As follicles begin to mature, they begin to secrete estrogen (low levels)

what happens to uterus during menstrual phase?

• Functional layer of endometrium from previous cycle is being shed (menstruation).

• Endometrium = <4mm

what happens to hormones during early- mid proliferative phase?

• GnRH—pulsations decrease

• FSH—high, begins to fall

• LH—low

• Estrogen—rising

• Progesterone--low

what happens to ovaries during early- mid proliferative phase?

• Late follicular phase- Dominant follicle develops antrum (see larger follicle on ultrasound)

• Progesterone still low, rises slightly near day 10

what happens to uterus during early- mid proliferative phase?

• New functional layer develops in response to estrogen stimulation.

  • new endometrial glands & spiral arteries/veins.

• Endometrium = 11mm

• 3 line sign seen

what happens to hormones during late proliferative phase?

• GnRH—pulsations increase

• FSH—begins to rise for surge 

• LH—begins to rise for surge

• Estrogen—high (crest)

• Progesterone—smaller peak

what happens to ovaries during late proliferative phase?

• Very late follicular phase- Oocyte within Graafian follicle moves toward wall.  Follicle measures 2.5-3cm

• Estrogen secretion peaks prior to ovulation

• Progesterone also rises and peaks, still lower than estrogen.

what happens to uterus during late proliferative phase?

• New functional layer is nearly complete. 

• See “3 lines” on ultrasound w/ definite hypoechoic halo

• Cervical mucus continues to thin

• Endometrium = 11-12mm

what happens to hormones during ovulatory phase?

• GnRH—pulsations increase

• FSH—small surge followed by immediate fall back to baseline

• LH—large surge followed by immediate fall back to baseline

• Estrogen—falling for short time

• Progesterone—falling for short time

what happens to ovaries during ovulatory phase?

• Oocyte in Graafian follicle completes 1^st meiotic division forming secondary oocyte.

• LH surge causes Graafian follicle to rupture, releasing oocyte

• Ruptured follicle forms corpus luteum under influence of LH

what happens to uterus during ovulatory phase?

• Cervix slightly open, receptive to sperm.

• Endometrium = 14 mm

• See “3 lines” on ultrasound

  • very prominent hypoechoic halo around central echogenic line

what happens to hormones during secretory phase?

• GnRH—pulsations low

• FSH—low

• LH—low

• Estrogen—high but lower peak prior to ovulation

• Progesterone—very high, coming to peak

what happens to ovaries during secretory phase?

• Corpus luteum secretes primarily progesterone and some estrogen

• CL appears:

  • thick walled

  • cystic

  • often complex/ containing debris

what happens to uterus during secretory phase?

• Endometrial glands begin to secrete nutrients (prep for zygote implantation)

• Endometrium becomes “thick and lush”

  • receptive to implantation

• 3 line sign replaced by thick echogenic endometrium on ultrasound

• Cervical mucus becomes thick again

what happens to hormones during late secretory phase (days 23-25)?

• GnRH—pulsations low

• FSH—low

• LH—low

IF NO Pregnancy:

• Estrogen—beginning to fall

• Progesterone—beginning to fall

what happens to ovaries during late secretory phase (days 23-25)?

• corpus luteum begins to degenerate

  • Due to low LH (& FSH) levels

• CL cystic structure begins to collapse, involute

  • often contains debris.

what happens to uterus during late secretory phase (days 23-25)?

• As progesterone/estrogen levels fall, endometrial glands & spiral vessels begin to atrophy & die.

• Endometrium still thick & hyperechoic.

• Endometrium = 9-16mm

what happens to hormones during late secretory phase (days 26-28)?

• GnRH—pulsations low

• FSH—low

• LH—low

IF NO Pregnancy:

• Estrogen—low

• Progesterone—low

what happens to ovaries during late secretory phase (days 26-28)?

• Corpus luteum forms corpus albicans (“white body”), basically a scar.

• No longer secreting progesterone or estrogen

what happens to uterus during late secretory phase (days 26-28)?

• Endometrial glands & spiral vessels atrophy & die; functional endometrial endometrium begins to detach from basal layer.

• Endometrium thick & hyperechoic w/posterior enhancement.

• Endometrium = 9-16mm

what uterine phase is this (and endometrial thickness)?

late menstrual phase (1-4mm)

what ovarian phase is this (days included)?

follicular (day -15)

what uterine phase is this (and endometrial thickness)?

proliferative (5-8 mm)

what ovarian phase is this (days included)?

follicular (6-13 days)

what uterine phase is this (and endometrial thickness)?

late proliferative (11 mm)

what ovarian phase is this?

follicular

what uterine phase is this (endometrial thickness)?

late secretory (9-16 mm)

what ovarian phase is this (days included)?

luteal (days 14-25)

what ovarian phase is this (days included)?

ovulatory (day 14 ish)

different “types” of amenorrhea?

transient

intermittent

permanent

amenorrhea can be the result of…

a dysfunction of the hypothalamus, pituitary, ovaries, uterus or vagina

two categories of amenorrhea:

primary

secondary

what is primary amenorrhea?

when menstruation fails to take take place at all.

• Menarche does not occur in a young girl aged 16

what is secondary amenorrhea?

occurs in women who have started menstruation but have had the absence of menses for the equivalent of three menstrual cycles or 6 months

what is oligomenorrhea?

infrequent or very light menstruation

• when a woman has menstrual periods that occur at intervals of greater than 35 days, with only 4-9 periods in a year, she is considered to have oligomenorrhea

what is premature ovarian failure?

• POF

• primary ovarian defect characterized by a lack of menarche (primary amenorrhea) or premature depletion of ovarian follicles before the age of 40 years (secondary amenorrhea.

why does POF put women at risk for other health conditions?

because drop of estrogen and progesterone

POF puts women at risk for other health conditions such as:

• Osteoporosis

• Low thyroid function

• Addison’s disease

• Heart disease risk

what is menopause?

A transition period in a woman’s life usually (but not always) occurring during her late 40s or early 50s.

what occurs during menopause?

• ovaries cease to produce ova

  • less estrogen and progesterone

• Hormone levels become unstable

  • estrogen and progesterone levels keep surging; then reach a low point until levels become permanently low

  • ovaries slowly stop responding to FSH and LH

  • endometrium not stimulated to proliferate or grow

  • No menses occurs

what occurs post menopause?

• uterus becomes small and fibrotic due to muscle atrophy

• ovaries fail to produce any follicles after menopause

  • makes the estrogen level in the blood reduced

  • causes the endometrial lining to become thin and atrophied

What occurs the further into menopause a woman is?

• the smaller their uterus becomes

• the smaller the ovaries become

  • decrease in size due to absence of folliculogenesis

what does the postmenopausal ovary look like on US?

• hypoechoic

• ovoid structure

• can be difficult to image/identify due to absence of follicles

what is the exception to the ovaries getting smaller in menopause?

if patient is receiving HRT (hormone replacement therapy), there may not be any changes to ovarian volume

what does this image depict?

post menopausal uterus

what does this image depict?

post menopausal ovaries

how does endometrium appear post menopause? exception to this?

• Endometrium appears as a thin, homogeneous, and echogenic line

  • should measure 4 mm or less

  • be smooth and uniform

• Exception: women on HRT (7 mm or less)

reasons for post menopausal bleeding?

• Endometrial atrophy

• Endometrial polyps

• Submucosal fibroids

• Endometrial hyperplasia

• Endometrial carcinoma

• Estrogen withdrawal

when is the best time to image a PMB patient?

directly after bleeding has stopped

in normal PMB patient, if endometrium is greater than 5mm or appears irregular, what may be needed?

further investigation may be needed

• sonohysterography

• biopsy

• hysteroscopy.