The menstrual cycle

• what is menustration?

  breaking down of uterus lining
• how long does it last?

  28 days
• FSH function?

  stimulates an egg to mature in ovaries
• oestrogen function?

  stimulates uterus lining to thicken
• progesterone function?

  maintains uterus lining
• LH function?

  stimulates release of egg on day 14
• week 1?


  menustration (period)
• what happens to uterus lining in week 2?

  builds up into thick spongy layer
• why does uterus lining build up in week 2?

  prepare uterus lining for a fertilised egg
• what happens to unfertilised eggs?

  break down
• what happens to fertilised eggs?

  implant into uterus lining
• what occurs on day 14?

  ovulation
• what days are fertilisation most likely?

  14-16
• what happens to uterus lining if egg is fertilised in week 4?

  it remains thick so embryo can be embedded and obtain useful nutrients
• what is contraception?

  prevention of fertilisation
• how does hormonal contraception work?

  prevent ovulation by thickening muccus at cervix to prevent sperm passing
• examples of hormonal contraception?

  hormone pills, implants, injections
• examples of barrier methods?

  condoms
• function of barrier methods?

  stop sperm reaching egg
• FSH stimulates ovaries to produce which hormone?

  oestrogen
• as oestrogen levels increase?

  starts to inhibit FSH production (negative feedback)
• when oestrogen levels get high..(LH)?

  release of LH is stimulated resulting in ovulation
• what does progesterone inhibit?

  LH and FSH
• what is menustration triggered by?

  fall in oestrogen and progesterone
• what does menstrual cycle prepare for?

  implantation of egg into uterus