Anatomy & Physiology of Anatomy & Physiology of the Female Reproductive the Female Reproductive

TractTract

External Genital OrgansExternal Genital Organs

mons pubismons pubis labia majoralabia majora labia minoralabia minora

– prepuce (clitoral hood)prepuce (clitoral hood)– frenulum of the labia minora = fourchettefrenulum of the labia minora = fourchette

vestibule of the vaginavestibule of the vagina– external urethral orificeexternal urethral orifice

paraurethral glands (Skene’s glands) [prostate]paraurethral glands (Skene’s glands) [prostate] Bartholin's glandBartholin's gland

Pubococcygeus MusclePubococcygeus Muscle

main part of levator animain part of levator ani– most likely muscle to be damaged during childbirthmost likely muscle to be damaged during childbirth– supports the bladder, urethra, vagina, and rectumsupports the bladder, urethra, vagina, and rectum

injuriesinjuries– cystocelecystocele– cystourethrocele or urethrocystocelecystourethrocele or urethrocystocele– rectocelerectocele– urinary stress incontinence (weakening of urinary stress incontinence (weakening of

pubovaginalis part of levator ani) => Kegel exercisepubovaginalis part of levator ani) => Kegel exercise

– vaginal orificevaginal orifice hymenhymen

– greater vestibular glandsgreater vestibular glands Bartholin’s glands [bulbourethral glands]Bartholin’s glands [bulbourethral glands]

arterial supplyarterial supply– two external pudendal arteriestwo external pudendal arteries– one internal pudendal arteryone internal pudendal artery

venous drainage: internal venous drainage: internal pudendal veinspudendal veins

Lymph DrainageLymph Drainage

The external genitalia, anus, and anal canal drain to the superficial inguinal nodes.

The lower one third of the vagina drains to the sacral nodes and the internal and common iliac nodes.

The cervix drains to the external or internal iliac and sacral nodes

Lymph, cont’dLymph, cont’d

The lower uterus drains to the external iliac nodes

The upper uterus drains into the ovarian lymphatics to the lumbar nodes. The lymphatics of the ovaries drain out of the pelvis to the lumbar nodes

InnervationInnervation– ilioinguinal nerveilioinguinal nerve– genital branch of the genitofemoral genital branch of the genitofemoral

nervenerve– perineal branch of the femoral perineal branch of the femoral

cutaneous nerve of thighcutaneous nerve of thigh– perineal nerveperineal nerve

Pelvic VisceraPelvic Viscera

Urogenital organs…– bladder, uterus, adnexa, and rectum

Also have…the sigmoid colon, cecum, and ileum are components of the pelvic anatomy.

Pelvic VisceraPelvic Viscera urinary organsurinary organs

– uretersureters pass medial to origin of uterine artery and pass medial to origin of uterine artery and

continues to level of ischial spine, where is crossed continues to level of ischial spine, where is crossed superiorly by the uterine artery. Then passes close superiorly by the uterine artery. Then passes close to lateral portion of vaginal fornix and enters to lateral portion of vaginal fornix and enters posterosuperior angle of bladderposterosuperior angle of bladder

– urinary bladderurinary bladder hollow viscus with strong muscular wallshollow viscus with strong muscular walls trigone of bladdertrigone of bladder

– urethra - about 4 cm long, anterior to vaginaurethra - about 4 cm long, anterior to vagina rectumrectum

– LigamentsLigaments

round ligament of uterus - attaches anterior-inferiorly round ligament of uterus - attaches anterior-inferiorly to uterotubal junctionsto uterotubal junctions

ligament of ovary - attached to uterus, posterior-ligament of ovary - attached to uterus, posterior-inferior to uterotubal junctionsinferior to uterotubal junctions

broad ligament - encloses body of uterus, freely broad ligament - encloses body of uterus, freely moveablemoveable

transverse cervical ligaments - extend from cervix and transverse cervical ligaments - extend from cervix and lateral parts of vaginal fornix to lateral walls of pelvislateral parts of vaginal fornix to lateral walls of pelvis

uterosacral ligaments - pass superiorly and slightly uterosacral ligaments - pass superiorly and slightly posteriorly from sides of cervix to middle of sacrum, posteriorly from sides of cervix to middle of sacrum, can be palpated through rectum as pass posteriorly at can be palpated through rectum as pass posteriorly at sides of rectum. Hold cervix in normal relationship to sides of rectum. Hold cervix in normal relationship to sacrum.sacrum.

Broad LigamentBroad Ligament

Contains between its layers the fallopian tube; the ovary and the round ligament; the uterine and ovarian blood vessels, nerves, lymphatics, and fibromuscular tissue; and a portion of the ureter as it passes lateral to the uterosacral ligaments over the lateral angles of the vagina and into the base of the bladder

Internal Genital OrgansInternal Genital Organs

vaginavagina– fornixfornix– rectouterine pouch (pouch of Douglas)rectouterine pouch (pouch of Douglas)– sphincters of vaginasphincters of vagina

pubovaginalis musclepubovaginalis muscle urogenital diaphragmurogenital diaphragm bulbospongiosus musclebulbospongiosus muscle

– lymphatic drainagelymphatic drainage superior part into internal and external iliac lymph superior part into internal and external iliac lymph

nodesnodes middle part into the internal iliac lymph nodesmiddle part into the internal iliac lymph nodes vestibule into superficial inguinal lymph nodesvestibule into superficial inguinal lymph nodes

UterusUterus

– 7-8 cm long, 5-7 cm wide, 2-3 cm thick7-8 cm long, 5-7 cm wide, 2-3 cm thick– projects superior-anteriorly over urinary projects superior-anteriorly over urinary

bladderbladder– two major partstwo major parts

body (superior 2/3s)body (superior 2/3s)– fundusfundus

cervix (inferior 1/3)cervix (inferior 1/3)– internal osinternal os– external osexternal os– anterior lipanterior lip– posterior lipposterior lip– lined with columnar, mucus-secreting epitheliumlined with columnar, mucus-secreting epithelium

isthmus = a transitional zone between body and isthmus = a transitional zone between body and cervixcervix

– wall of uterus consists of 3 layers:wall of uterus consists of 3 layers:

Perimetrium/serosa - outer serous coat, Perimetrium/serosa - outer serous coat, peritoneum supported by thin layer of peritoneum supported by thin layer of connective tissueconnective tissue

myometrium - 12-15 mm smooth muscle, myometrium - 12-15 mm smooth muscle, main branches of blood vessels and nerves of main branches of blood vessels and nerves of uterus are in this layeruterus are in this layer

endometrium - inner mucous coatendometrium - inner mucous coat

uterine tubes uterine tubes

– 10-12 cm long, 1 cm diameter10-12 cm long, 1 cm diameter– extend laterally from cornua of uterusextend laterally from cornua of uterus– 4 parts4 parts

infundibuluminfundibulum– distal enddistal end– abdominal ostium, about 2 mm in diameterabdominal ostium, about 2 mm in diameter– 20-30 fimbriae20-30 fimbriae– ovarian fimbria is attached to ovaryovarian fimbria is attached to ovary

ampullaampulla– tortuous parttortuous part– widest and longest part, over 1/2 its lengthwidest and longest part, over 1/2 its length– fertilization occurs herefertilization occurs here– MostMost common site for ectopic common site for ectopic

isthmusisthmus– short 2.5 cm, narrow, thick-walled part of tube short 2.5 cm, narrow, thick-walled part of tube

that enters the uterine cornuthat enters the uterine cornu uterine partuterine part

– short segment that passes through thick short segment that passes through thick myometrium of uterusmyometrium of uterus

– uterine ostium (smaller than abdominal uterine ostium (smaller than abdominal ostium)ostium)

OvariesOvaries

– oval, almond-shaped, 3 cm long, 1.5 cm oval, almond-shaped, 3 cm long, 1.5 cm wide, 1 cm thickwide, 1 cm thick

– ligamentsligaments superior (tubal) end of ovary is connected to superior (tubal) end of ovary is connected to

lateral wall of pelvis by suspensory ligament of lateral wall of pelvis by suspensory ligament of the ovarythe ovary

– contains ovarian vessels and nervescontains ovarian vessels and nerves ligament of ovary - connects inferior (uterine) end ligament of ovary - connects inferior (uterine) end

of ovary to lateral angle of uterusof ovary to lateral angle of uterus

– surface of ovary is not covered by surface of ovary is not covered by peritoneumperitoneum

oocyte expelled into peritoneal cavity oocyte expelled into peritoneal cavity

PelvisPelvis

The bony and ligamentous pelvic mechanism is designed to…– protect the pelvic viscera– support the vertebral column– facilitate locomotion

The pelvic girdle protects the viscera contained within its cavity from all ordinary trauma

PelvisPelvis

The bony pelvis is formed anteriorly and laterally by the innominate bones and posteriorly by the sacrum and coccyx

The pelvic girdle is adapted for strength, support, and locomotion.

In the erect position, the pelvic girdle is inclined forward.

Man vs. WomanMan vs. Woman

The female pelvic inlet is oval; the male pelvic inlet is heart shaped.

The female pelvis has a more regular outline than the male pelvis, in which the sacral promontory is more prominent and the sacrum is longer and more curved.

Female Bony PelvisFemale Bony Pelvis wider, shallower, and has larger superior and wider, shallower, and has larger superior and

inferior pelvic apertures than male pelvisinferior pelvic apertures than male pelvis hip bones farther aparthip bones farther apart ischial tuberosities are farther apart because ischial tuberosities are farther apart because

of wider pubic archof wider pubic arch sacrum is less curved, which increases the sacrum is less curved, which increases the

size of the inferior pelvic aperture and the size of the inferior pelvic aperture and the diameter of the birth canaldiameter of the birth canal

obturator foramina is oval obturator foramina is oval

Types of Bony PelvisTypes of Bony Pelvis

anthropoid = AP diameter > transverse anthropoid = AP diameter > transverse diameterdiameter– 23% females23% females

platypelloidplatypelloid– uncommonuncommon

android = wide transverse diameter, posterior android = wide transverse diameter, posterior part of aperture is narrowpart of aperture is narrow– 32% females32% females

gynecoid = most spacious obstetricallygynecoid = most spacious obstetrically– 43% females43% females

Superior Pelvic Aperture Superior Pelvic Aperture

AP diameter = measurement from AP diameter = measurement from the midpoint of the superior border the midpoint of the superior border of pubic symphysis to the midpoint of pubic symphysis to the midpoint of sacral promontoryof sacral promontory

transverse diameter = greatest transverse diameter = greatest width, measured from linea width, measured from linea terminalis on one side to this line terminalis on one side to this line on opposite sideon opposite side

oblique diameter = measurement from oblique diameter = measurement from one iliopubic eminence to the opposite one iliopubic eminence to the opposite sacroiliac jointsacroiliac joint

midplane diameter = interspinous midplane diameter = interspinous diameter or distance between ischial diameter or distance between ischial spines and cannot be measured. Is spines and cannot be measured. Is estimated by palpating the estimated by palpating the scarospinous ligament through the scarospinous ligament through the vagina. The length of this ligament = vagina. The length of this ligament = about half the midplane diameter.about half the midplane diameter.

determine prominence of ischial spinesdetermine prominence of ischial spines– < 9.5 cm may prevent passage of fetus< 9.5 cm may prevent passage of fetus

PhysiologyPhysiology

HypothalamusHypothalamus Anterior PituitaryAnterior Pituitary OvaryOvary Endometrium & outflow tractEndometrium & outflow tract

HypothalamusHypothalamus Release of GnRH (gonadotropin-Release of GnRH (gonadotropin-

releasing hormone), also called releasing hormone), also called LHRH, into the pituitary portal LHRH, into the pituitary portal circulation via the pituitary stalkcirculation via the pituitary stalk

The menstrual cycle does not The menstrual cycle does not ‘begin’ here!! All are inter-related !‘begin’ here!! All are inter-related !

HypothalamusHypothalamus What triggers the release of GnRH?What triggers the release of GnRH?

– Unclear but in animal studies dopamine is Unclear but in animal studies dopamine is inhibitory & norepinephrine is stimulatoryinhibitory & norepinephrine is stimulatory

– For normal gonadotropin release, GnRH For normal gonadotropin release, GnRH must be released in pulses. The pulse must be released in pulses. The pulse frequency & amplitude are critical for frequency & amplitude are critical for normal mensesnormal menses

– Decrease in pulse frequency will decrease Decrease in pulse frequency will decrease LH release & increase FSHLH release & increase FSH

– Increase pulse frequency will increase LH & Increase pulse frequency will increase LH & decrease FSHdecrease FSH

Anterior PituitaryAnterior Pituitary

Gonadotrophs respond to the GnRH Gonadotrophs respond to the GnRH by producing FSH (follicle stimulating by producing FSH (follicle stimulating hormone) & LH (Luteinizing hormone) & LH (Luteinizing hormone) into the general circulationhormone) into the general circulation

Release at this level is also controlled Release at this level is also controlled by circulating levels of estrogen & by circulating levels of estrogen & progesterone (gonadal steroids)…progesterone (gonadal steroids)…positive & negative feedbackpositive & negative feedback

Anterior PituitaryAnterior Pituitary

Stores & releases FSH & LHStores & releases FSH & LH Day 1-7, follicular phase: estrogen from Day 1-7, follicular phase: estrogen from

the ovary will stimulate storage of FSH & the ovary will stimulate storage of FSH & LH(in the pituitary)…also inhibits secretionLH(in the pituitary)…also inhibits secretion

Later in follicular phase with increasing Later in follicular phase with increasing estrogen levels (enlarging follicle) effect on estrogen levels (enlarging follicle) effect on gonadotrophs changes to gonadotrophs changes to stimulatorystimulatory allowing for a secretion of LH which allowing for a secretion of LH which triggers ovulation triggers ovulation

Under the influence of LH, the Under the influence of LH, the follicle begins to secrete follicle begins to secrete progesteroneprogesterone shortly before shortly before ovulationovulation

Low level of Low level of progesteroneprogesterone will will induce the induce the FSH surgeFSH surge that occurs that occurs immediately prior to ovulationimmediately prior to ovulation

FSH SurgeFSH Surge

– matures the oocyte (stimulates matures the oocyte (stimulates gametogenesisgametogenesis

– produces proteolytic enzymes needed produces proteolytic enzymes needed for follicle rupturefor follicle rupture

– Increases the # of LH Increases the # of LH receptors(ovarian) required for receptors(ovarian) required for optimal progesterone production in optimal progesterone production in the luteal phasethe luteal phase

LH surgeLH surge– increase in intrafollicular proteolytic

enzymes that destroy the basement membrane and allow follicular rupture

– luteinization of the granulosa cells and theca, resulting in increased progesterone production

– resumption of meiosis in the oocyte, thus preparing it for fertilization

– an influx of blood vessels into the follicle, preparing it to become a corpus luteum.

After ovulation, the secretion of After ovulation, the secretion of estrogen & progesteroneestrogen & progesterone in high in high concentrations from the concentrations from the corpus corpus luteumluteum inhibits both gonadotrophs inhibits both gonadotrophs & GnRH& GnRH

As the corpus luteum dies off the As the corpus luteum dies off the hormone levels subside & FSH hormone levels subside & FSH resumes the cycleresumes the cycle

OvaryOvary

By the fifth week of embryonic life, By the fifth week of embryonic life, germ cells have formed the ovarygerm cells have formed the ovary

Maximum # of eggs the ovary is Maximum # of eggs the ovary is able to produce is at 20 weeks of able to produce is at 20 weeks of gestation… 6-7 million!gestation… 6-7 million!

1-2 million at birth1-2 million at birth 300,000 at the onset of puberty!300,000 at the onset of puberty!

OvaryOvary

The functional unit is the FOLLICLEThe functional unit is the FOLLICLE Oocyte (frozen in the first stage of Oocyte (frozen in the first stage of

meiosis) surrounded by granulosa meiosis) surrounded by granulosa cells & adjacent stromal cells…cells & adjacent stromal cells…Theca cells.Theca cells.

FSH will target the granulosa cellsFSH will target the granulosa cells LH will target the thecal & stromal LH will target the thecal & stromal

cellscells

Ovary, cont’dOvary, cont’d

As the follicle matures, Antrum As the follicle matures, Antrum develops around the oocytedevelops around the oocyte

A bunch of follicles will develop A bunch of follicles will develop around day 7 of cycle…a dominant around day 7 of cycle…a dominant follicle will win!follicle will win!

Ovary cont’dOvary cont’d

Rising estrogen levels from the Rising estrogen levels from the maturing follicle itself will ‘prime’ the maturing follicle itself will ‘prime’ the follicle for the LH surge.follicle for the LH surge.

When estrogen levels reach 200pg/ml When estrogen levels reach 200pg/ml or greater for longer than 48 hours, the or greater for longer than 48 hours, the LH surge occursLH surge occurs

The granulosa cells become luteinized The granulosa cells become luteinized just prior to ovulation & begin to just prior to ovulation & begin to produce progesteroneproduce progesterone

Progesterone rise is Progesterone rise is responsible for...responsible for...

Facilitates the positive feedback Facilitates the positive feedback action of estradiol in initiating the action of estradiol in initiating the LH surgeLH surge– LH surge occurs about 36 hours prior LH surge occurs about 36 hours prior

to ovulationto ovulation Responsible for the FSH peakResponsible for the FSH peak

OvaryOvary

An avascular area will develop on An avascular area will develop on the wall of the follicle & with the the wall of the follicle & with the help of proteolytic enzymes help of proteolytic enzymes ovulation occurs. ovulation occurs.

The oocyte is picked up by the The oocyte is picked up by the fimbriae of the tubefimbriae of the tube

If not met by a sperm will If not met by a sperm will degenerate in 12-24 hours!degenerate in 12-24 hours!

OvaryOvary

After ovulation, luteinization will After ovulation, luteinization will transform the ruptured follicle into transform the ruptured follicle into a corpus luteum which produces a corpus luteum which produces estrogen & progesterone for the estrogen & progesterone for the next 12- 16 daysnext 12- 16 days

If not aided by secretion of hCG, If not aided by secretion of hCG, the corpus luteum will become the the corpus luteum will become the corpus albicanscorpus albicans

AndrogensAndrogens

Androstenedione & testosterone Androstenedione & testosterone are also secreted & can alter the are also secreted & can alter the ability of the ovary to respond to ability of the ovary to respond to FSH & LH…may create atretic FSH & LH…may create atretic follicles early on follicles early on

TWO CELL THEORYTWO CELL THEORY

……of ovarian steroidogenesisof ovarian steroidogenesis Theca cells produce androgens Theca cells produce androgens

under the influence of LHunder the influence of LH Granulosa cells convert the Granulosa cells convert the

androgens to estrogen under the androgens to estrogen under the influence of FSHinfluence of FSH

EndometriumEndometrium

Contains receptors for both estradiol & Contains receptors for both estradiol & progesteroneprogesterone

Estradiol causes the proliferation, Estradiol causes the proliferation, steady increase in thickness of liningsteady increase in thickness of lining

When the corpus luteum starts When the corpus luteum starts producing progesterone; the producing progesterone; the proliferative effect of estradiol is proliferative effect of estradiol is neutralized & endometrial growth neutralized & endometrial growth ceasesceases

EndometriumEndometrium

The lining now becomes The lining now becomes SECRETORY with the endometrial SECRETORY with the endometrial vessels coiling & preparing to shedvessels coiling & preparing to shed

If no baby… corpus luteum stops If no baby… corpus luteum stops producing estrogen & progesterone. producing estrogen & progesterone. This withdrawal of steroid support This withdrawal of steroid support from the endometrium causes from the endometrium causes endometrial breakdownendometrial breakdown

Why don’t women bleed to Why don’t women bleed to death every month??death every month??

Vascular spasmVascular spasm ThrombosisThrombosis Resumption of endometrial Resumption of endometrial

proliferation under the influence of proliferation under the influence of unopposed estrogenunopposed estrogen

Myometrial ischemia - Myometrial ischemia - dysmenorrheadysmenorrhea