The Ovarian Cycle (typically 28 day cycle)

• Follicular phase (days 1-10 of cycle)

• 1. primordial follicle ------> primary follicle (squamous cells) (cuboidal cells)
• 2. primary follicle ------> secondary follicle; follicle cells ------> stratified epithelium (granulosa)
• 3. ovary cortex forms theca folliculi around granulosa ;theca folliculi & granulosa produce estrogens
• 4. granulosa form jelly-like zona pellucida
• 5. fluid-filled space called antrum develops
• 6. primary follicle now becomes a secondary follicle ;granulosa cells begin to form corona radiata ;secondary (vesicular) follicle reaches ovary surface

• Ovulatory phase (days 11-14 of cycle)
  

• fluid filled antrum increases in size ;corona radiata begins to separate from wall
  
• ovulation - secondary oocyte (surrounded by the corona radiata) bursts from the ovary -->into the peritoneal cavity (fimbriae pick up!)
  
• mittelschmerz - pain associated with ovulation
  

• Luteal phase (days 14-28 of cycle)
  

• corpus luteum forms from granulosa and thecal cells remaining from the bursting site; it secretes progesterone and some estrogen
• YES pregnancy -> secrete more progesterone
• NO pregnancy -> whole structure will degenerate (no more progesterone)

Category: Physiology Notes