Menstrual cycles

• Ovulation


  The release of an egg from the ovary every 28 days
• Menstrual cycle


  The 28-day cycle involving the release of an egg and the preparation of the uterus lining
• Key hormones in the menstrual cycle

  • Follicle Stimulating Hormone (FSH)
  • Luteinizing Hormone (LH)
  • Estrogen
  • Progesterone
• Follicle Stimulating Hormone (FSH)


  Causes an egg to mature in the ovary
• Luteinizing Hormone (LH)

  Causes the mature egg to be released (ovulation)
• Estrogen


  Maintains the uterus lining
• Progesterone


  Maintains the uterus lining and prevents further egg maturation and release
• Menstrual cycle


  1. FSH released by pituitary gland

  2. FSH causes egg maturation and estrogen production in ovary

  3. Estrogen inhibits further FSH release

  4. LH released by pituitary gland

  5. LH triggers ovulation

  6. Ovary releases progesterone

  7. Progesterone maintains uterus lining

  8. If no fertilization, progesterone levels fall, uterus lining shed (period)