Anatomy

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Anatomy Physiology of the Female Reproductive
Tract

• Anna Mae Smith, MPAS, PA-C
• Lock Haven University
• Physician Assistant Program

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External Genital Organs

• mons pubis
• labia majora
• labia minora
• prepuce (clitoral hood)
• frenulum of the labia minora fourchette
• vestibule of the vagina
• external urethral orifice
• paraurethral glands (Skenes glands) prostate
• Bartholin's gland

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Pubococcygeus Muscle

• main part of levator ani
• most likely muscle to be damaged during
  childbirth
• supports the bladder, urethra, vagina, and rectum
• injuries
• cystocele
• cystourethrocele or urethrocystocele
• rectocele
• urinary stress incontinence (weakening of
  pubovaginalis part of levator ani) Kegel
  exercise

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• vaginal orifice
• hymen
• greater vestibular glands
• Bartholins glands bulbourethral glands
• arterial supply
• two external pudendal arteries
• one internal pudendal artery
• venous drainage internal pudendal veins

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Lymph 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

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Lymph, contd

• 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

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• Innervation
• ilioinguinal nerve
• genital branch of the genitofemoral nerve
• perineal branch of the femoral cutaneous nerve of
  thigh
• perineal nerve

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Pelvic Viscera

• Urogenital organs
• bladder, uterus, adnexa, and rectum
• Also havethe sigmoid colon, cecum, and ileum are
  components of the pelvic anatomy.

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Pelvic Viscera

• urinary organs
• ureters
• pass medial to origin of uterine artery and
  continues to level of ischial spine, where is
  crossed superiorly by the uterine artery. Then
  passes close to lateral portion of vaginal
  fornix and enters posterosuperior angle of
  bladder
• urinary bladder
• hollow viscus with strong muscular walls
• trigone of bladder
• urethra - about 4 cm long, anterior to vagina
• rectum

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• Ligaments
• round ligament of uterus - attaches
  anterior-inferiorly to uterotubal junctions
• ligament of ovary - attached to uterus,
  posterior-inferior to uterotubal junctions
• broad ligament - encloses body of uterus, freely
  moveable
• transverse cervical ligaments - extend from
  cervix and lateral parts of vaginal fornix to
  lateral walls of pelvis
• uterosacral ligaments - pass superiorly and
  slightly posteriorly from sides of cervix to
  middle of sacrum, can be palpated through rectum
  as pass posteriorly at sides of rectum. Hold
  cervix in normal relationship to sacrum.

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Broad 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

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Internal Genital Organs

• vagina
• fornix
• rectouterine pouch (pouch of Douglas)
• sphincters of vagina
• pubovaginalis muscle
• urogenital diaphragm
• bulbospongiosus muscle
• lymphatic drainage
• superior part into internal and external iliac
  lymph nodes
• middle part into the internal iliac lymph nodes
• vestibule into superficial inguinal lymph nodes

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• Uterus
• 7-8 cm long, 5-7 cm wide, 2-3 cm thick
• projects superior-anteriorly over urinary bladder
• two major parts
• body (superior 2/3s)
• fundus
• cervix (inferior 1/3)
• internal os
• external os
• anterior lip
• posterior lip
• lined with columnar, mucus-secreting epithelium
• isthmus a transitional zone between body and
  cervix

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• wall of uterus consists of 3 layers
• Perimetrium/serosa - outer serous coat,
  peritoneum supported by thin layer of connective
  tissue
• myometrium - 12-15 mm smooth muscle, main
  branches of blood vessels and nerves of uterus
  are in this layer
• endometrium - inner mucous coat

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• uterine tubes
• 10-12 cm long, 1 cm diameter
• extend laterally from cornua of uterus
• 4 parts
• infundibulum
• distal end
• abdominal ostium, about 2 mm in diameter
• 20-30 fimbriae
• ovarian fimbria is attached to ovary
• ampulla
• tortuous part
• widest and longest part, over 1/2 its length
• fertilization occurs here
• Most common site for ectopic

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• isthmus
• short 2.5 cm, narrow, thick-walled part of tube
  that enters the uterine cornu
• uterine part
• short segment that passes through thick
  myometrium of uterus
• uterine ostium (smaller than abdominal ostium)

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• Ovaries
• oval, almond-shaped, 3 cm long, 1.5 cm wide, 1 cm
  thick
• ligaments
• superior (tubal) end of ovary is connected to
  lateral wall of pelvis by suspensory ligament of
  the ovary
• contains ovarian vessels and nerves
• ligament of ovary - connects inferior (uterine)
  end of ovary to lateral angle of uterus
• surface of ovary is not covered by peritoneum
• oocyte expelled into peritoneal cavity

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Pelvis

• 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

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Pelvis

• 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.

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Man 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.

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Female Bony Pelvis

• wider, shallower, and has larger superior and
  inferior pelvic apertures than male pelvis
• hip bones farther apart
• ischial tuberosities are farther apart because of
  wider pubic arch
• sacrum is less curved, which increases the size
  of the inferior pelvic aperture and the diameter
  of the birth canal
• obturator foramina is oval

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Types of Bony Pelvis

• anthropoid AP diameter transverse diameter
• 23 females
• platypelloid
• uncommon
• android wide transverse diameter, posterior
  part of aperture is narrow
• 32 females
• gynecoid most spacious obstetrically
• 43 females

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Superior Pelvic Aperture

• AP diameter measurement from the midpoint of
  the superior border of pubic symphysis to the
  midpoint of sacral promontory
• transverse diameter greatest width, measured
  from linea terminalis on one side to this line on
  opposite side

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• oblique diameter measurement from one iliopubic
  eminence to the opposite sacroiliac joint
• midplane diameter interspinous diameter or
  distance between ischial spines and cannot be
  measured. Is estimated by palpating the
  scarospinous ligament through the vagina. The
  length of this ligament about half the midplane
  diameter.
• determine prominence of ischial spines

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Physiology

• Hypothalamus
• Anterior Pituitary
• Ovary
• Endometrium outflow tract

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Hypothalamus

• Release of GnRH (gonadotropin-releasing hormone),
  also called LHRH, into the pituitary portal
  circulation via the pituitary stalk
• The menstrual cycle does not begin here!! All
  are inter-related !

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Hypothalamus

• What triggers the release of GnRH?
• Unclear but in animal studies dopamine is
  inhibitory norepinephrine is stimulatory
• For normal gonadotropin release, GnRH must be
  released in pulses. The pulse frequency
  amplitude are critical for normal menses
• Decrease in pulse frequency will decrease LH
  release increase FSH
• Increase pulse frequency will increase LH
  decrease FSH

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Anterior Pituitary

• Gonadotrophs respond to the GnRH by producing FSH
  (follicle stimulating hormone) LH (Luteinizing
  hormone) into the general circulation
• Release at this level is also controlled by
  circulating levels of estrogen progesterone
  (gonadal steroids)positive negative feedback

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Anterior Pituitary

• Stores releases FSH LH
• Day 1-7, follicular phase estrogen from the
  ovary will stimulate storage of FSH LH(in the
  pituitary)also inhibits secretion
• Later in follicular phase with increasing
  estrogen levels (enlarging follicle) effect on
  gonadotrophs changes to stimulatory allowing for
  a secretion of LH which triggers ovulation

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• Under the influence of LH, the follicle begins to
  secrete progesterone shortly before ovulation
• Low level of progesterone will induce the FSH
  surge that occurs immediately prior to ovulation

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FSH Surge

• matures the oocyte (stimulates gametogenesis
• produces proteolytic enzymes needed for follicle
  rupture
• Increases the of LH receptors(ovarian) required
  for optimal progesterone production in the luteal
  phase

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LH 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.

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• After ovulation, the secretion of estrogen
  progesterone in high concentrations from the
  corpus luteum inhibits both gonadotrophs GnRH
• As the corpus luteum dies off the hormone levels
  subside FSH resumes the cycle

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Ovary

• By the fifth week of embryonic life, germ cells
  have formed the ovary
• Maximum of eggs the ovary is able to produce is
  at 20 weeks of gestation 6-7 million!
• 1-2 million at birth
• 300,000 at the onset of puberty!

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Ovary

• The functional unit is the FOLLICLE
• Oocyte (frozen in the first stage of meiosis)
  surrounded by granulosa cells adjacent stromal
  cellsTheca cells.
• FSH will target the granulosa cells
• LH will target the thecal stromal cells

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Ovary, contd

• As the follicle matures, Antrum develops around
  the oocyte
• A bunch of follicles will develop around day 7 of
  cyclea dominant follicle will win!

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Ovary contd

• Rising estrogen levels from the maturing follicle
  itself will prime the follicle for the LH
  surge.
• When estrogen levels reach 200pg/ml or greater
  for longer than 48 hours, the LH surge occurs
• The granulosa cells become luteinized just prior
  to ovulation begin to produce progesterone

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Progesterone rise is responsible for...

• Facilitates the positive feedback action of
  estradiol in initiating the LH surge
• LH surge occurs about 36 hours prior to ovulation
• Responsible for the FSH peak

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Ovary

• An avascular area will develop on the wall of the
  follicle with the help of proteolytic enzymes
  ovulation occurs.
• The oocyte is picked up by the fimbriae of the
  tube
• If not met by a sperm will degenerate in 12-24
  hours!

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Ovary

• After ovulation, luteinization will transform the
  ruptured follicle into a corpus luteum which
  produces estrogen progesterone for the next 12-
  16 days
• If not aided by secretion of hCG, the corpus
  luteum will become the corpus albicans

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Androgens

• Androstenedione testosterone are also secreted
  can alter the ability of the ovary to respond
  to FSH LHmay create atretic follicles early on

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TWO CELL THEORY

• of ovarian steroidogenesis
• Theca cells produce androgens under the influence
  of LH
• Granulosa cells convert the androgens to estrogen
  under the influence of FSH

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Endometrium

• Contains receptors for both estradiol
  progesterone
• Estradiol causes the proliferation, steady
  increase in thickness of lining
• When the corpus luteum starts producing
  progesterone the proliferative effect of
  estradiol is neutralized endometrial growth
  ceases

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Endometrium

• The lining now becomes SECRETORY with the
  endometrial vessels coiling preparing to shed
• If no baby corpus luteum stops producing
  estrogen progesterone. This withdrawal of
  steroid support from the endometrium causes
  endometrial breakdown

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Why dont women bleed to death every month??

• Vascular spasm
• Thrombosis
• Resumption of endometrial proliferation under the
  influence of unopposed estrogen
• Myometrial ischemia - dysmenorrhea