Reproductive hormones and the menstrual cycle

• • Oestrogen is produced by the ovaries

  • It causes the lining of the uterus to grow

  • It also inhibits the production of FSH from the pituitary gland, but stimulates the production of LH
• • LH is produced by the pituitary gland

  • It stimulates ovulation, the release of the egg on day 14
• • Progesterone is produced in the ovaries by the remains of the follicle, now called the corpus luteum

  • Progesterone maintains the lining of the womb during the second half of the cycle and also inhibits release of FSH and

  LH
• • If the egg is not fertilised, the corpus luteum breaks down and stop making progesterone. The lining of the

  womb breaks down and passes out of the woman’s vagina during menstruation
• • If, however, the egg is fertilised, the corpus luteum carries on making progesterone, the lining is not shed

  and menstruation does not happen (the first sign that tells a woman she is pregnant is when her monthly

  period stops)
• Later on in pregnancy, the placenta secretes progesterone, taking over the role of the corpus luteum
• • Inside a woman’s ovaries, there are hundreds of thousands of cell that could develop into mature eggs.

  Every month, one of these grows inside a ball of cells called a follicle
• • A hormone secreted by the pituitary gland called FSH (Follicle Stimulating Hormone) causes the egg cell to

  mature inside the follicle

  • FSH also causes the ovaries to start producing oestrogen
• inside a woman's ovaries, there are hundreds of thousands of cells that could develop into mature eggs. every month, one of these grows inside of a ball of cells called a follicle

  • a hormone secreted by the pituitary gland called FSH causes the egg cell to mature inside the follicle
  • FSH also causes the ovaries to start producing oestrogen