menstrual cycle

• 1. Menstruation occurs and the uterus lining is shed.
  2. Ovulation occurs and egg is released from ovary.
  3. Uterus lining continues to build up until menstruation, but if egg is fertilised, ovary releases oestrogen.
• • FSH from pituitary helps the egg mature.

  • Oestrogen from ovaries thickens the uterus lining.

  • LH from pituitary releases egg (ovulation).

  • Progesterone from ovaries thickens uterus lining.
• Falling levels of progesterone and oestrogen trigger menstruation.