Female Reproductive System

• Female Reproductive Anatomy


  • Ovaries
  • Accessory ducts (Uterine tubes, Uterus, Vagina)
• Ovaries


  • Held in place by several ligaments (Ovarian ligament, Suspensory ligament, Broad ligament)
  • Blood supply: ovarian arteries and the ovarian branch of the uterine artery
  • Surrounded by a fibrous tunica albuginea
  • Two regions: Cortex (contains ovarian follicles), Medulla (large blood vessels & nerves)
• Follicle


  Immature egg (oocyte) surrounded by Follicle cells (one cell layer thick) and Granulosa cells (outer layer)
• Follicle development


  1. Primordial follicle

  2. Primary follicle

  3. Secondary follicle

  4. Late secondary follicle

  5. Vesicular (Graafian) follicle

  6. Ovulation
• Ovulation is the ejection of an oocyte from a ripening follicle
• The ruptured follicle develops into a corpus luteum
• Uterine Duct System


  • Uterine (fallopian) tubes or oviducts
  • Uterus
  • Vagina
• Uterine Tubes


  • Ampulla (distal expansion with infundibulum near ovary, usual site of fertilization)
  • Ciliated fimbriae of infundibulum create currents to move oocyte into uterine tube
  • Isthmus (constricted region where tube joins uterus)
  • Oocyte is carried along by peristalsis and ciliary action
  • Nonciliated cells nourish the oocyte and the sperm
• Uterus


  • Body (major portion)
  • Fundus (rounded superior region)
  • Isthmus (narrowed inferior region)
  • Cervix (narrow neck, or outlet; projects into the 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
• Supports of the Uterus

  • Mesometrium (lateral support: portion of the broad ligament)
  • Lateral cervical (cardinal) ligaments (from cervix & superior part of vagina to walls of pelvis)
  • Uterosacral ligaments (secure uterus to sacrum)
  • Round ligaments (bind to anterior wall)
• Uterine Wall


  • Perimetrium (serous layer, visceral peritoneum)
  • Myometrium (interlacing layers of smooth muscle)
  • Endometrium (mucosal lining)
  • Stratum functionalis (functional layer, changes in response to ovarian hormone cycles, is shed during menstruation)
  • Stratum basalis (basal layer, forms new functionalis after menstruation, unresponsive to ovarian hormones)
• Uterine Vascular Supply


  • Uterine arteries (arise from internal iliac arteries, arcuate arteries in myometrium, radial arteries to endometrium, spiral arteries in stratum functionalis, straight arteries in stratum basalis)
  • Spasms of spiral arteries leads to shedding of stratum functionalis
• Vagina


  • Birth canal and organ of copulation
  • Urethra embedded in anterior wall
  • Fornix (recess that surrounds vaginal attachment to cervix)
  • Hymen (mucous membrane that covers vaginal opening prior to sexual intercourse)
• External Genitalia (Vulva or Pudendum)


  • Mons pubis (fatty area overlying pubic symphysis)
  • Labia majora (hair-covered, fatty skin folds)
  • Labia minora (skin folds lying within labia majora)
  • Vestibule (recess between labia minora)
  • Greater vestibular glands (homologous to bulbourethral glands, release mucus into vestibule for lubrication)
  • Clitoris (erectile tissue hooded by a prepuce, glans clitoris is exposed portion)
  • Perineum (diamond-shaped region between pubic arch and coccyx, bordered by ischial tuberosities laterally)
• Female Sexual Response


  • Initiated by touch and psychological stimuli
  • Clitoris, vaginal mucosa, and breasts engorge with blood
  • Vestibular gland secretions lubricate the vestibule
  • Orgasm is accompanied by muscle tension, increase in pulse rate and blood pressure, and rhythmic contractions of the uterus
  • Females do not have a refractory period after orgasm and can experience multiple orgasms in a single sexual experience
  • Orgasm is not essential for conception
• 
  

  Oogenesis

  Production of female gametes

  Begins in the fetal period, but development does not complete until after puberty

  1. Primordial follicle

  2. Primary follicle

  3. Secondary follicle

  4. Late secondary follicle

  5. Vesicular (Graafian) follicle
• Establishing the Ovarian Cycle


  • During childhood, until puberty: Ovaries secrete small amounts of estrogens, estrogen inhibits release of GnRH
  • At puberty: Leptin from adipose tissue decreases the estrogen inhibition, GnRH, FSH, and LH are released, in about four years, an adult cyclic pattern is achieved & menarche occurs
• Ovarian Cycle Phases


  • Follicular Phase (1-14)
  • Ovulation (Midcycle)
  • Luteal Phase (14-26, corpus luteum activity)
• Follicular Phase


  1. Oogenesis: Primordial follicle activated, Follicle enlarges to primary follicle, Becomes a secondary follicle, Becomes a late secondary follicle, Becomes a vesicular follicle (Graafian follicle), The primary oocyte completes meiosis I

  2. Hormonal Interactions: GnRH release of FSH and LH, Growth of follicles & release of estrogen, Increased levels of estrogen inhibit further release of FSH and LH, FSH and LH are now stored, This enhances further estrogen output, Follicles (ovary) release more estrogen
• Ovulation


  • Ovary wall ruptures and expels the secondary oocyte
  • Mittelschmerz (twinge of pain sometimes felt at ovulation)
  • If more than one secondary oocyte is released, results in fraternal twins if fertilized
  • Surge of LH at day 14 triggers ovulation and transforms ruptured follicle into corpus luteum
• Luteal Phase


  1. Oogenesis: Corpus luteum secretes progesterone & estrogen, If no pregnancy: Corpus luteum degenerates into a corpus albicans, If pregnancy: Corpus luteum produces hormones until placenta takes over at about 3 months

  2. Hormonal Interactions: Corpus luteum produces Inhibin, Progesterone, Estrogen, Once corpus luteum has degenerated, the blockade of FSH and LH ends, Cycle starts over
• Uterine (Menstrual) Cycle Phases


  • Menstrual phase (Days 1–5)
  • Proliferative (preovulatory) phase (Days 6–14)
  • Secretory (postovulatory) phase (Days 15–28, 14-days constant)
• Menstrual Phase


  Ovarian hormones are at their lowest levels, Gonadotropins are beginning to rise, Stratum functionalis is shed and the menstrual flow occurs
• Proliferative Phase


  Estrogen levels prompt generation of new functional layer, Increased synthesis of progesterone receptors in endometrium
• Secretory Phase


  Progesterone levels prompt further development of endometrium, Glandular secretion of glycogen, Formation of the cervical mucus plug
• If fertilization does not occur


  Corpus luteum degenerates, Progesterone levels fall, Spiral arteries kink and spasm, Endometrial cells begin to die, Spiral arteries constrict again, then relax and open wide, Rush of blood fragments, weakened capillary beds & the functional layer sloughs
• Effects of Estrogens


  • Promote oogenesis and follicle growth in the ovary
  • Exert anabolic effects on the female reproductive tract
  • Support the rapid, but short-lived growth spurt at puberty
  • Maintain low total blood cholesterol and high HDL levels
  • Facilitates calcium uptake
  • Induce secondary sex characteristics (growth of breasts, increased deposit of subcutaneous adipose in hips and breasts, widening and lightening of the pelvis)
• Effects of Progesterone


  • Works with estrogen to establish and regulate the uterine cycle
  • Inhibits uterine motility
  • Helps prepare the breasts for lactation
• Stages of Pregnancy


  • Fertilization
  • Embryonic Period (fertilization through 8 weeks)
  • Fetal Period (beginning 9th week, until birth)
• Fertilization


  1. Sperm (viable for 24-48 hours) combine with secondary oocyte (viable for 12-24 hours) to form a fertilized egg = ZYGOTE

  2. ZYGOTE undergoes cleavage after 36 hours and becomes BLASTOMERES (2 daughter cells)

  3. EMBRYO at 16 cell divisions = MORULA

  4. MORULA at 100 cell divisions = BLASTOCYST which reaches the uterus in 3-4 days; it floats for 2-3 days before implanting into the endometrium (12 days from ovulation)

  5. The OUTER part becomes the TROPHOBLAST and evolves into the PLACENTA

  6. The INNER cells evolve to form the EMBRYO
• Embryo Germ Layers


  • Ectoderm (nervous tissue and epidermis)
  • Mesoderm (muscles, skeletal structures)
  • Endoderm (digestive, respiratory, urogenital systems)
• Human Chorionic Gonadotropin (HCG)


  • Secreted initially by the TROPHOBLAST which becomes part of the placenta
  • Stimulates the CORPUS LUTEUM (in the ovary) to secrete progesterone and estrogen until the PLACENTA takes over the function at ~ 3 months
• Genetic Sex of the Offspring

  • Determined by sperm (Females XX, Males XY)
  • SRY sex determining region on the chromosome
  • Development of external genitalia
  • Genital tubercle - penis or clitoris
  • Urethral Fold - urethra or labia minora
  • Labioscrotal fold - scrotum or labia majora
  • Gonad Development (Males: 7th week, Females: 8th week)
• Birth Control Methods


  • Hormonal Birth Control
  • IUD
  • Barrier methods
  • Emergency Contraceptives
  • Permanent Birth Control
• Endometriosis is the growth of the endometrial tissue outside of the uterus
• Endometriosis Symptoms


  • Premenstrual pain
  • Severe menstrual pain
• Breast cancer is the 2nd leading cause of cancer deaths in women in U.S. next to lung cancer
• Breast Cancer Risk Factors

  • Mutated BRCA 1 and BRCA 2 increase risk
  • Detected by mammogram and ultrasound
• Ovarian Cancer is the leading cause of death from all gynecological malignancies
• Cervical Cancer is usually caused by HPV and detected by pap smear (in most cases)