Menstrual Cycle

• Menstrual cycle

  Cycle that happens in females
• Menstrual cycle (days 1-5)

  1. Menstruation

  2. Uterus lining breaks down and is lost with unfertilized egg
• Menstrual cycle (days 5-14)

  1. Uterus lining starts to thicken

  2. Estrogen produced and secreted from ovaries causes uterus lining to thicken
• Ovulation (day 14)


  Release of egg from ovary into oviduct
• Menstrual cycle (days 14-22)

  1. Estrogen continues to thicken uterus lining

  2. Progesterone produced to maintain uterus lining thickness
• If female is not pregnant

  Progesterone levels drop, uterus lining no longer maintained, menstruation occurs
• If female is pregnant

  Embryo embeds on uterus lining, no menstruation for 9 months