puberty + menstrual cycle

• Puberty


  Where a child's body develops into an adult's body. It happens over many years and usually takes place between the ages of 10 and 16. It happens slightly earlier for females than males.
• Puberty


  • The body releases sex hormones that starts the development of secondary sexual characteristics
  • The main reproductive hormone for males is testosterone, which is produced by the testes and stimulates sperm production
  • The main reproductive hormone for females is oestrogen, which is produced in the ovaries and brings about many physical changes in the body, causes eggs to mature, and is involved in the menstrual cycle
• Menstrual cycle


  • The process of getting the uterus ready for a fertilised egg (pregnancy).
  • It is a continuous cycle that takes around 28 days.
• Stages of the menstrual cycle

  1. Menstruation (lining of the uterus is shed through the vagina)

  2. Lining of the uterus builds up to become thick and spongey with lots of blood vessels

  3. An egg develops and is released from the ovary (ovulation)

  4. Lining of the uterus is maintained ready to receive a fertilised egg
• Hormones involved in the menstrual cycle

  • FSH (follicle-stimulating hormone)
  • Oestrogen
  • LH (luteinising hormone)
  • Progesterone
• FSH


  • Causes an egg to mature in one of the ovaries, which creates a structure called a follicle.
  • Also causes the ovaries to start producing oestrogen.
• Oestrogen


  • Causes the lining of the uterus to grow into a thick spongey wall with lots of blood vessels.
  • High levels between day 4 and day 14 when the lining is being built.
  • Stimulates the production of LH and inhibits the production of FSH.
• LH


  • Causes an egg to be released on day 14 (ovulation).
  • The level of LH peaks on day 14.
• Progesterone


  • Maintains the lining of the uterus between day 14 and day 28.
  • Inhibits the production of LH and FSH.