female reproductive Flashcards
gonads and accessory structures
ovaries
- make ova
- secrete estrogen (estradiol, estrone, estriol) and progesterone
Accessory
- eterine tubes
- uterus
- vagina
internal
in pelvic cavity Ovaries Uterine tubes Uterus Vagina
sacs of peritoneum around uterus
Vesicouterine pouch between bladder and uterus
Rectouterine pouch between rectum and uterus
Ligaments
Ovarian ligament - anchors ovary medially to uterus
Suspensory ligament - anchors ovary laterally to pelvic wall
Mesovarium - suspends ovary
Suspensory ligament and mesovarium part of broad ligament – supports uterine tubes, uterus, and vagina
ovary blood supply and layers
ovarian arteries and ovarian branch of the uterine arteries
surrounded by fibrous tunica albuginea
germinal epithelium = outer layer
two poorly defined regions:
- outer cortex which houses forming gametes
- inner medulla which houses blood vessels and nerves
Ovarian follicles
immature egg (oocyte) surrounded by
- follicle cells (one layer thick)
- granulosa cells (over one layer)
Several stages of development
- primordial follicle = single layer of follicle cells and oocyte
- more mature follicles = several layers of granulosa cells
- vesicular (antral or tertiary) follicle = fully mature with fluid-filled antrum –> follicle bulges from ovary surface
ovulation and corpus luteum
ovulation = ejection of oocyte from ripening follicle
corpus luteum develops from ruptured follicle after ovulation
duct system contact with ovary
no contact
oocytes are cast into peritoneal canvity where some are lost
uterine tubes
anatomy
function
receive ovulated oocyte - usual site of fertilization
Isthmus = constricted region where tube joins uterus
ampulla
Distal expansion with infundibulum near ovary - ciliated fimbriae of infundibulum create current
- oocytes carried along by peristalsis and ciliary action
- nonciliated cells (peg cells) nourish oocyte and sperm
- covered externally by peritoneum
- mesosalpinx = mesentery that supports uterine tubes
Uterus: cervix, cervical canal, and cervical glands
cervix = narrow nexk, or outlet projecting into vagina
cervical canal communicates with vagina via external os and uterine body via internal os
cervical glands secrete mucus that blocks sperm entry except during midcycle
the rest of the uterus
hollow, thick walled, muscular organ
receives, retains, and nourishes fertilized ovum
Anteverted - inclined forward; retroverted - inclined backward
body = major portion fundus = rounded superior region isthmus = narrow inferior region
uterus histology
perimetrium = serous layer (visceral peritoneum) myometrium = interlacing layers of smooth muscle endometrium = mucosal lining
endometrial layers
Stratum functionalis
- changes in response to ovarian hormone cycles
- sheds during menstruation
stratum basalis
- forms new functionalis after menstruation
- unresponsive to ovarian hormones
uterine vascular supply
Uterine arteries arise from internal iliacs; branch into
Arcuate arteries in myometrium; branch into
Radial arteries in endometrium; branch into
- Straight arteries –> stratum basalis
- Spiral arteries –> stratum functionalis (Degenerate and regenerate; spasms –> shedding of functionalis layer during menstruation)
Cervical cancer
- 450,000 women each year - kills half. In US those who dies are those who didn’t get regular screening and those with immune deficiencies
- most common bt 30-50
Risks: basically all cases related to HPV
Papanicolau (pap) smear for detection
-every 2-3 years. every 5 years if negative HPV test. May discontinue at age 65 if normal screenings prior
HPV vaccine
-3 dose vaccine
Recommended for 11- and 12-year-old girls and boys as well as catch up immunization for those under 26. Those between the age of 26-45 can consider it if they are considered at risk. Does not prevent the need for screening. Does not cover all strains of HPV that cause cervical cancer.
vagina: gross anatomy
- Thin-walled tube 8-10 cm in length
- -Birth canal and organ of copulation
- Extends between bladder and rectum from cervix to exterior
- Urethra parallels course anteriorly; embedded in anterior wall
- Vaginal fornix = upper end of vagina surrounding cervix
vagina microscopic anatomy
layers
HIV access
hymen
Layers of wall
- fibroelastic adventitia
- smooth muscle muscularis
- stratified squamous mucosa with rugae
dendritic cells in mucosa may provide route for HIV transmission
Mucosa near vaginal orifice forms incomplete partition called hymen - ruptures with intercourse
External genitaila: mons pubis, labia majora/minora
Mons pubis - fatty area overlying pubic symphysis
Labia majora - hair-covered, fatty skin folds
-Counterpart of male scrotum
Labia minora - skin folds lying within labia majora
- Join at posterior end of vestibule fourchette
- Vestibule - recess within labia minora
external genitalia: greater vestibular glands, clitoris, and perineum
Greater vestibular glands
- Flank vaginal opening
- Homologous to bulbo-urethral glands
- Release mucus into vestibule for lubrication
Clitoris - anterior to vestibule
- glans of the clitoris = exposed portion
- prepuce of clitoris = hoods glans
- counterpart of glans penis
Perineum
- diamond shaped region bt pubic arch and coccyx
- bordered by ischial tuberosities laterally
Mammary glands
Modified sweat glands consisting of 15–25 lobes
Function in milk production
Areola - pigmented skin surrounding nipple
Suspensory ligaments (Cooper’s ligaments) – attach breast to underlying muscle
Lobules within lobes contain glandular alveoli that produce milk
breast cancer: stats and contraceptives
Invasive breast cancer most common malignancy, second most common cause of cancer death in U.S. women
13% will develop condition
Use of hormonal contraceptives quadruple risk of most aggressive breast cancer (triple negative breast cancer) in women under the age of 40
Breast cancer: cause and risk factors
Usually arises from epithelial cells of smallest ducts; eventually metastasize
Risk factors include
- Early onset of menstruation and late menopause
- No pregnancies or first pregnancy late in life
- No or short periods of breast feeding
- Family history of breast cancer
- Hormonal contraceptive use
10% due to hereditary defects, including mutations to genes BRCA1 and BRCA2
50 – 80% develop breast cancer
Greater risk of ovarian cancer as well
70% of women with breast cancer have no known risk factors
Breast cancer diagnosis
Early detection via self-examination and mammography
-X-ray examination
-American Cancer Society recommends screening every year for women 40 and over. This is controversial because it has not shown to increase survival. Increased risk from unnecessary invasive diagnostic tests such as biopsies,
-U.S. Prevention Services Task Force on Breast Cancer Screening recommends screening every two years in ages 50 and over
These recommendations are for asymptomatic women with no significant risk factors.
-Women who have symptoms or have significant risk factors will have mammography recommendations based on their individual case, not on the general population screening recommendations
Oogenesis and follicular development
- Formation of gametes in ovary
- Oogenesis begins before females are born
- Essentially same steps of meiosis as spermatogenesis
- During early fetal development, primordial (primitive) germ cells migrate from yolk sac to ovaries
- Germ cells then differentiate into oogonia – diploid (2n) stem cells
- Before birth, most germ cells degenerate – atresia
- A few develop into primary oocytes that enter meiosis I during fetal development
- Each covered by single layer of flat follicular cells – primordial follicle
- About 200,000 to 2,000,000 at birth, 40,00 remain at puberty, and around 400 will mature during a lifetime
Follicular development (primordial follicle to secondary follicle)
Each month from puberty to menopause, FSH and LH stimulate the development of several primordial follicles
-Usually, only one reaches ovulation
Primordial follicles develop into primary follicles
- Primary oocyte surrounded by granulosa cells
- Forms zona pellucida between granulosa cells and primary oocyte
- Stromal cells begin to form theca folliculi
Primary follicles develop into secondary follicles
- Theca differentiates into theca interna secreting estrogens and theca externa secreting androgens
- Granulosa cells secrete follicular fluid in antrum
- Innermost layer of granulosa cells attaches to zona pellucida forming corona radiata
follicular development: secondary follicle to zygote
Secondary follicle becomes mature (graffian) follicle
- Just before ovulation, diploid primary oocyte completes meiosis I
- Produces 2 unequal sized haploid (n) cells – first polar body is discarded and secondary oocyte
At ovulation, secondary oocyte expelled with first polar body and corona radiata
If fertilization does not occur, cells degenerate
If a sperm penetrates secondary oocyte, meiosis II resumes
Secondary oocyte splits into 2 cells of unequal size – second polar body (also discarded) and ovum or mature egg
Nuclei of sperm cell and ovum unite to form diploid zygote
comparison of oogenesis and spermatogenesis
S = 4 viable sperm with 3-4% error rate
O = 1 viable gamete + 3 polar bodies with 20% error rate
unequal divisions ensure oocyte has ample nutrients for 6-7 day journey to uterus
polar bodies degenerate and die
Two parts of female reproductive cycle
Ovarian cycle – series of events in ovaries that occur during and after maturation of oocyte
Uterine (menstrual) cycle – concurrent series of changes in uterine endometrium preparing it for arrival of fertilized ovum
Hormones: GnRH and FSH
Gonadotropin-releasing hormone (GnRH)
- Secreted by hypothalamus controls ovarian and uterine cycle
- Stimulates release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from anterior pituitary
FSH (anterior pituitary)
- Initiate follicular growth
- Stimulate ovarian follicles to secrete estrogens
Hormones: LH
LH (anterior pituitary)
Stimulates further development of ovarian follicles
Stimulate ovarian follicles to secrete estrogens
Stimulates thecal cells of developing follicle to produce androgens to be converted into estrogens
Triggers ovulation
Promotes formation of corpus luteum – produces estrogens, progesterone, relaxin and inhibin
Hormones: estrogen and progesterone
Estrogens secreted by ovarian follicles
Promote development and maintenance of female reproductive structures and secondary sex characteristics
Increases protein anabolism including building strong bones
Lowers blood cholesterol
Inhibit release of GnRH, LH and FSH
Progesterone
Secreted mainly by corpus luteum
Works with estrogens to prepare and maintin endometrium for implantation and mammary glands for milk production
Inhibits secretion of GnRH and LH
hormones: relaxin and inhibin
Relaxin
Produced by corpus luteum
Relaxes uterus by inhibiting contraction of myometrium
At end of pregnancy, increases flexibility of pubic symphysis and dilates uterine cervix
Inhibin
Secreted by granulosa cells of growing follicles and by corpus luteum
Inhibits secretion of FSH and LH
4 phases of reproductive cycle and typical duration
Typical duration 24-35 days
Assume a duration of 28 days
Menstrual phase
Preovulatory phase
Ovulation
Postovulatory phase
Menstrual phase/ mensruation
Roughly first 5 days of cycle
First day of menstruation is day 1 of new cycle
Events in ovaries
Under FSH influence, several primordial follicles develop into primary follicles ad then into secondary follicles
Takes several months
Follicle that begins to develop in one cycle may not mature for several cycles later
Events in uterus
Menstrual discharge occurs because declining levels of estrogens and progesterone stimulate release of prostaglandins causing uterine spiral arterioles to constrict
Cells deprived of oxygen begin to die
Only stratum basilis remains
Preovulatory phase ovaries
More variable in length
Lasts from days 6-13 in a 28 day cycle
Events in ovaries
Some of secondary follicles begin to secrete estrogens and inhibin
Dominant follicle – one follicle outgrown all others
-Estrogens and inhibin of dominant follicle decrease FSH causing other follicles to stop growing
-Fraternal (nonidentical) twins result when 2 or 3 secondary follicles become codominant and are ovulated and fertilized at the same time
Normally, one dominant follicle becomes the mature (graffian) follicle
In ovarian cycle, menstrual and preovulatory phases are termed follicular phase because follicles are growing
preovulatory phase uterus
Estrogens stimulate repair of endometrium
Cells of stratum basalis undergo mitosis to form new stratum functionalis
Thickness of endometrium doubles
In uterine cycle, preovulatory phase is the proliferative phase because endometrium is proliferating
ovulation and twins
Rupture of mature (graffian) follicle and release of secondary oocyte
Day 14 of 28 day cycle
High levels of estrogens exert a positive feedback effect on cells secreting LH and GnRH
Ovary wall ruptures, expels secondary oocyte with its corona radiata to peritoneal cavity
Mittelschmerz - twinge of pain sometimes felt at ovulation
1–2% of ovulations release more than one secondary oocyte, which, if fertilized, results in fraternal twins
Identical twins result from fertilization of one oocyte, then separation of daughter cells
Postovulatory phase: ovary
Duration most constant of phases
Lasts for 14 days in 28 day cycle (day 15-28)
Events in one ovary
After ovulation, mature follicle collapses to form corpus luteum under the influence of LH
Secretes progesterone, estrogen, relaxin and inhibin
In the ovarian cycle, this is the luteal phase
corpus luteum
hCG role
If oocyte not fertilized, corpus luteum lasts 2 weeks
- Degenerates in corpus albicans
- As levels of progesterone, estrogens and inhibin decrease, release of GnRH, FSH, and LH rise sue to loss of negative feedback
- Follicular growth resume as new ovarian cycle begins
If oocyte is fertilized, corpus luteum lasts more than 2 weeks
-Human chorionic gonadotropin (hCG) produced by chorion of embryo about 8 days after fertilization stimulates corpus luteum
Postovulatory phase uterus
Progesterone and estrogens produced by corpus luteum promote growth of endometrium
Because of secretory activity of endometrial glands, this is the secretory phase of uterine cycle
Changes peak about 1 week after ovulation when an embryo might arrive in uterus
If fertilization does not occur, levels of progesterone and estrogens decline due to degeneration of corpus luteum
Withdrawal of estrogens and progesterone due to the degenerating corpus lutem causes menstruation
Establishing ovarian cycle during childhood until puberty
Ovaries secrete small amounts of estrogens
Estrogen inhibits release of GnRH
Onset of puberty linked to amount of adipose tissue via hormone leptin
If leptin levels adequate hypothalamus less sensitive to estrogen as puberty nears; releases GnRH in rhythmic pulse-like manner –> FSH and LH release –>ovarian hormone release
establishing the ovarian cycle (continued)
Gonadotropin levels increase ~ four years; no ovulation; no pregnancy
Then adult cyclic pattern achieved and menarche occurs
First menstrual period
~ Three years before cycle regular and all ovulatory
effects of estrogen while establishing ovulation
- ovulation stuff
- sex characteristic stuff
- metabolic stuff
Promote oogenesis and follicle growth in ovary
Exert anabolic effects on female reproductive tract
Support rapid but short-lived growth spurt at puberty
Induce secondary sex characteristics
- Growth of breasts
- Increased deposit of subcutaneous fat (hips and breasts)
- Widening and lightening of pelvis
Metabolic effects (not true secondary sex characteristics)
- Maintain low total blood cholesterol and high HDL levels
- Facilitate calcium uptake
Effects of progesterone
Progesterone works with estrogen to establish and regulate uterine cycle
Promotes changes in cervical mucus
Effects of placental progesterone during pregnancy
-Inhibits uterine motility
-Helps prepare breasts for lactation
Female sexual response
Initiated by touch and psychological stimuli
Clitoris, vaginal mucosa, bulbs of vestibule, and breasts engorge with blood; nipples erect
Vestibular gland secretions lubricate vestibule
Orgasm accompanied by muscle tension, increase in pulse rate and blood pressure, and rhythmic contractions of uterus
menopause
Has occurred when menses have ceased for an entire year
No equivalent to menopause in males
-Males continue to produce sperm well into eighth decade of life, though numbers and motility decrease
menopause: effects of declining estrogen levels
Atrophy of reproductive organs and breasts
Irritability and depression in some
Hot flashes as skin blood vessels undergo intense vasodilation
Gradual thinning of skin and bone loss
Increased total blood cholesterol levels and falling HDL
Menopause treatment with estrogen-progesterone
Women’s Health Initiative research reported increased risk of heart disease (51%), invasive breast cancer (24%), stroke (31%), dementia (risk doubled)
Smallest does for shortest time alright to reduce symptoms if no breast cancer or mutated BRCA gene
