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    • Female Reproductive Endocrinology Chapter 18
    •  
    • Anatomy
      • Vulva – external genitalia
      • Vagina
        • Functions:
          • Sperm, menstrual flow passage
          • Receptacle for penis
          • Birth canal
        • Rugae
        • Acidic environment
    •  
      • Uterus
        • Functions:
          • Sperm transport
          • Implantation fert’d ovum
          • Fetal dev’t
          • Labor
          • Menstruation
        • Cervix secretes mucus
      • Uterus – cont’d
        • Three histological layers
          • Perimetrium – outside
          • Myometrium – sev muscle layers + connective tissue
            • Forms bulk of uterine wall
          • Endometrium – closest to uterine cavity
            • Covered w/ epithelium
            • Vascular w/ tubular glands
            • Further divided  3 layers
              • Innermost shed w/ menstruation
              • Outermost  new inner layer during cycle
      • Oviducts
        • Transport
          • Peristalsis
          • Cilia
        • Isthmus, ampulla, infundibulum
        • Not static tube
      • Ovaries = gonads
        • Inner medulla, outer cortex
        • Gametogenesis, hormonogenesis
    •  
    • Ovaries
      • Prepubertal
        • Anatomy
          • Smooth outer germinal epithelium
          • Connective tissue
          • Cortex w/ ovarian follicles in stroma
        • Low quantities of sex steroid
          • Feedback inhibition of gonadotropins
      • Puberty  gonadotropins  sex steroids
        • LH  PKA  StAR  P450scc in partic cells
        • FSH  E2 secr’n in partic cells
    • Ovarian Cycle
      • Controls, controlled by hormones
      • Coupled to uterine cycle
      • Related to maturation ovarian follicles
        • Gonadotropin dependent
      • Two phases
        • Follicular
        • Luteal
    • Follicular Phase
      • Variable length
      • Maturing follicles secrete
        • 17  -estradiol
        • Inhibin
      • Absence functional CL
        • Plasma progesterone low
      • FSH elevated @ beginning, diminishes
        • High FSH impt to follicle selection, early maturation
      • As follicle dev’s, more E2, inhibin 
        • Decr’d FSH (neg feedback)
        • Decr’d LH
        • Upregulation ant pit GnRH receptors
      • E2 peaks @ midcycle  FSH/LH surge
      • Now new ability some ovarian cells to produce sex steroids (progesterone)
      • Now ovum released from mature follicle
    •  
    • Luteal Phase
      • Invariant 14 + 2 d length
      • CL begins, develops, dies
      • CL secretes progesterone (also E2, inhibin) as matures
        • Progesterone  postov decr LH, FSH (neg feedback)
        • Midluteal peak over week
        • E2 minimally elevated
      • Hormone secretion diminishes as CL declines
        • If no fertilization
        • Get sharp decline in plasma progesterone
      • Now less neg feedback due to progesterone
        •  FSH/LH again secreted
        • FSH influences new follicle selection, early maturation
    •  
    • Gametogenesis
      • Ovarian follicles named by maturation stage
      • Primordial
        • Primary oocyte
        • Squamous epithelium; single layer
          • Dev’s  granulosa cells
        • Growth & remodeling
        • 40  ; oocyte 15-25 
        • Quiescent
    •  
      • Primary follicle
        • Oocyte enlarges (80-100 m)
        • Follicle epithelium
          • Simple cuboidal
          • “ Granulosa cells”
          • Express FSH receptors
        • FSH response  organize, stratify granulosa cell layers
        • Zona pellucida (glycoprotein layer) deposits
        • Stroma begins to organize as theca
      • Secondary=preantral follicle
        • Granulosa proliferates, stratifies
          • Signaled by oocyte growth factors
            • Growth Differentiation Factor 9 (GDF-9)
            • Bone Morphological Protein 15 (BMP-15)
          • Mitosis and/or pattern of arrangement stim’d
            • Simple cuboidal  stratified, pseudostratified columnar
            • Diff layers have diff morphology, function
        • Granulosa cells produce activin
          • Stim’s FSH receptor synth
        • Granulosa cells become sensitive to FSH
          • Impt to selection
          • Impt to differentiation
          • Impt to maturation
    • Figure 9. The early differentiation of the granulosa cells during preantral folliculogenesis involves the expression of FSH receptors. Animal studies support the concept that this process involves an activin autocrine/paracrine mechanism. (Erickson GF: Dissociation of Endocrine and Gametogenic Ovarian Function. In Lobo, R. (ed.): Perimenopause. Serono Symposia, Springer-Verlaag, 1997. Reproduced with permission from Springer-Verlag, New York.)
      • Secondary follicle – cont’d
        • Granulosa cells connected by gap junctions
          • Synchronization
          • Nutrient transfer
        • Basement membr dev’s
        • When 6 layers granulosa
          • Definitive theca layer
          • Angiogenesis  blood supply to theca
      • Secondary follicle (cont’d)
        • Final 2 o follicle 100-200 
          • Fully grown oocyte w/ zp
          • Approx 9 layers granulosa
          • Basal lamina
          • Theca interna w/ capillary net
          • Theca externa
    • Granulosa cells
    • Thecal cells
      • Tertiary=antral follicle
        • Chamber
        • Follicular fluid contains hormones
          • Blood-derived
          • From oocyte
          • From granulosa cells
        • Cavitation signalled by follicle cells
        • Corona radiata = granulosa cells anchored to zp
        • Theca fully developed
      • Tertiary follicle – cont’d
        • Theca interna = steroid producing (androstenedione)
          • Extensive sER, cytoplasmic lipid droplets, tubular mitoch cristae
          • Receptors for LH, insulin
          • Richly vascularized
        • Theca externa
          • Smooth muscle cells
          • Autonomic neurons
    • Figure 12. Photomicrograph of an early tertiary follicle 0.4 mm in diameter at the cavitation or early antrum stage. zona pellucida (ZP); granulosa cells (GC); basal lamina (BL); theca interna (TI); theca externa (TE); granulosa mitosis (arrowheads). (Bloom W, Fawcett DW In A Textbook of Histology. Philadelphia, WB Saunders Company, Philadelphia 1975. With permission from Arnold.)
      • Preovulatory=Graafian follicle
        • Now single, dominant follicle
        • Overall size varies; deter’d by amt follicular fluid
        • Cumulus oophorus = oocyte + corona radiata
          • Will be expelled @ ovulation
        • Hyaluronic acid accumulates
          • Break attachment corona radiata and granulosa
        • LH surge induces completion 1 st meiotic division  2 o oocyte
          • 2 nd meiotic division @ fert’n
    •  
    • Ovulation
      • Induced by LH surge
      • Rupture
        • Follicle wall
        • Follicle cell layers
      •  Corona radiata w/ oocyte expelled into peritoneal cavity
    •  
    • Luteinization
      • Initiated by LH surge
      • CL forms from
        • Graunulosa lutein
        • Theca lutein
        • Assoc’d microvasculature
      • Defined life span
        • If no fertilization, involution & apoptosis 14 d after form’n
      • Contributes to next developing cohort of follicles
        • CL degeneration  decr’d E2, inhibin A
        •  incr’d FSH
        •  incr’d FSH in follic fluid of Graafian follicle
        •  dominant follicle selection, maturation
    • Atresia
      • Remaining 99.9% follicles
      • Apoptosis of oocyte, granulosa cells
        • Ligand signalling pathways  cell death
      • FSH=survival factor
        • Prevents apoptosis
    • Ovarian Steroidogenesis
      • Maturing follicles and CL
      • Maturing follicles – 2 adjacent impt pop’ns
        • Granulosa cells
        • Theca interna cells
      • CL – impt cells der’d from follicle after ov’n
        • Granulosa lutein
        • Theca lutein
      • Sex steroids
        • Prior to ov’n (from maturing follicle): E2
        • After ov’n (from CL): progesterone + E2
      • Book notes progesterone=distinctive female hormone
        • CL and placenta only
      • Cell pop’ns coordinate in prod’n sex steroids
    •  
      • Theca (interna & externa) express P450scc
        • Cholesterol  pregnenolone
        • Sensitive to LH
          •  cAMP  PKA  StAR  PBR  P450scc activity in inner mitoch membr
        • Pregnenolone  androgen pathway
          • Uses P450c17
        • Preovulatory LH surge 
          • Ovulation
          • Luteinization theca interna, granulosa
          • Development CL
      • Theca interna express aromatase (androgens  estrogens)
        • BUT once ovulation occurs, expression ceases
        • So decr’d secr’n estrogens from CL
      • Granulosa cells lack P450scc, P450c17
        • No cholesterol  pregnenolone
        • No further androgen synth
        • Rely on theca cell androgens
        • Insensitive to LH signal for androgen prod’n
          • EXCEPT when advanced follicle dev’d
            • Just prior to ov’n
            • Small numbers LH receptors expressed
            • LH stim’s steroidogenesis in these cells
            • Impt to luteinization
      • Granulosa cells – cont’d
        • BUT sensitive to FSH
          • FSH stim’n 
            • Proliferation granulosa cells
            • Secretion inhibin B
            • Expression aromatase through cAMP, PKA act’n
      • Granulosa cells express aromatase
        • Androgens  estrogens
        • Most impt source of E2
    •  
      • Granulosa lutein cells express P450scc
        • So can produce pregnenolone
      • BUT granulosa lutein cells lack P450c17
        • No androgen synth from pregnenolone
          • Rely on theca lutein cells for androgens
        • BUT progesterone synth from pregnenolone
        • Insensitive to LH signal to produce androgens
          • BUT small numbers LH receptors expressed in advanced follicle
          • LH  secr’n progesterone, secr’n inhibin A
      • Granulosa lutein cells express aromatase
        • Androgens  estrogens
        • Activated with LH
      • If pregnancy, interrelationships balanced also with placental cells
    •  
    • Endometrial (Uterine) Cycle
      • Coupled to ovarian cycle
        • Gametogenesis
        • Hormonogenesis
      • Three phases
      • Menstruation – during follicular phase
        • With demise of CL
        • Plasma progesterone decr’d
        • Uterine endometrium shed
          • Leaves basal portion of endometrial glands
        • 2-7 d (4 d avg)
        • 30 mL blood loss avg
      • Proliferative – during follicular phase
        • E2 dependent regeneration, growth of endometrium
        • E2 receptor binding @ remaining basal stratum  stromal, epithelial cell growth
      • Secretory – during luteal phase
        • Progesterone-dependent maturation of endometrium
        • Requires E2 prep’n endometrium
        • Now suitable for blastocyst implantation
    •  
    •  
    •  
    •  
    • Vaginal Cycle
      • After puberty
      • In response to estrogens
        • Changes w/ menstrual cycle
      • Early follicular phase
        • Epithelium rounded basal cells
      • Late follicular phase – maximum growth
        • Basal cells covered w/ flattened cells
        • Outermost cells keratinized
      • End luteal
        • Epith invaded w/ leukocytes, dead cells degen’d