puberty and the menstrual cycle

• at puberty your body starts releasing sex hormones, what do they do?

  they trigger secondary sexual characteristics, and in women cause eggs to mature
• women:

  main reproductive hormone - oestrogen

  produced by - ovaries

  causes - physical change and involved in the menstrual cycle
• Men:

  main reproductive hormone - testosterone

  produced by - testes

  stimulates - sperm production
• what happnes in stage one of the menstural cycle?

  menstruation starts, the uterus lining breaks down for about four days (there is a drop in progesterone), and unfertalised egg leaves in menstrual flow
• what happnes in stage two of the menstural cycle?

  the uterus wall thickens (due to oestrogen and progesterone), new egg follicle matures in ovary (due to FHS)
• what happnes in stage three of the menstural cycle?

  ovulation occurs (egg develops and is released from the ovary) (due to LH), uterus wall is at peak thickness
• what happnes in stage four of the menstural cycle?

  egg moves down the fallopian tube into the uterus (that remains thick due to progesterone) if its unfertalised, the cycle starts again
• what are the stages days in the menstural cycle?

  stage one : 0-5

  stage two : 5-13

  stage three : 14

  stage four : 14-28
• 2. oestrogen:

  produced in the ovaries

  causes the uteris lining to grow

  stimulates the release of LH and inhibits the release of FSH
• 1.FHS (follicle stimulating hormone) :

  produced in the pituitary gland

  causes an egg to mature in a follicle (in the ovaries)

  stimulates the ovaries to produce oestrogen
• 3. LH (luteinising hormone) :

  produced by the pituitary gland

  stimulates the release of an egg (ovulation) at day 14
• 4. progesterone

  produced in the ovaries (by follicle remains after ovulation)

  maintains uterus lining (2nd half of cycle)

  inhibits release of LH and FSH
• what does FHS do?

  makes eggs mature
• what does oestrogen do?

  makes the uterus lining grow
• what does LH do?

  stimulates egg release
• what does progesterone do?

  maintains the uterus lining