Puberty and the Menstrual Cycle

• During puberty reproductive hormones cause secondary sex characteristics to develop
• Testosterone stimulates sperm production
• Oestrogen is the main female reproductive hormone produced in the ovary. At puberty eggs begin to mature and one is released approximately every 28 days. This is called ovulation.
• Menstrual cycle

  • The uterus lining breaks down for 4 days
  • The uterus lining builds up again from day 4-14 into a thick spongy layer of blood vessels
  • An egg develops and is released from the ovary at day 14 : this is ovulation
  • The wall is maintained from day 14 until 28 but if there is no fertilised egg the spongy lining starts to break down
• FSH (follicle-stimulating hormone) is produced by the pituitary gland, causes the egg to mature in the ovaries and stimulates the ovaries to release oestrogen
• Oestrogen is produced by the ovaries, causes the lining in the uterus to grow, stimulates LH and inhibits FSH
• LH (luteinising hormone) is produced by the pituitary gland and stimulates the release of the egg (ovulation)
• Progesterone is produced in the ovaries, maintains the lining of the uterus for the second half of the cycle and inhibits the release of LF and FSH