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  • Hormones
    • Pituitary gland produces FSH
      • FSH causes egg to mature in the ovary, FSH causes ovaries to produce oestrogen
        • Oestrogen cause pituitary to produce LH
          • LH causes egg to be released from ovary
    • Different stages
      • FSH produced by the pituitary gland, causes an egg to mature in one of the ovaries, stimulates the ovaries to produce oestrogen
      • LH produced in the pituitary gland, stimulates the release of an egg at around the middle of the menstrual cycle
      • Oestrogen produced in the ovaries, causes pituitary to produce LH, inhibits the further release of FSH
    • The menstrual cylce
      • Stage 4 the wall is then maintained for about 14 days until day 28, if no fertilised egg has landed on the uterus by day 28 the lining starts to break down again
        • Stage 3 an egg is released from the ovary at day 14
          • Stage 2 the lining of the uterus builds up again, from day 4-14 into a thick spongy layer of blood vessels ready to receive a fertilised egg
            • Stage 1 when the bleeding starts, the uterus lining breaks down for about four days
    • Glands
      • The pituitary gland, this produces many important hormones including FSH and LH which are involved in the menstrual cycle
      • Ovaries produce oestrogen which is involved in the menstrual cycle
    • Hormones
      • Hormones are chemical messengers sent in the blood to activate target cells
      • Released directly into blood, carried in blood plasma and only affect particular cells called target cells
      • They tend to have long lasting effects, they travel at the speed of blood, they are produced by various glands.
    • Contraceptives
      • Progesterone reduces fertility by stimulating the production of thick cervical mucus which prevents any sperm getting through and reaching an egg
      • The pill contains oestrogen and progesterone, but they were worried oestrogen had side effects like blood clots, so they reduced the dosage of it
        • Pros are the pills over 99% at preventing pregnancy, it also reduces the chance of getting some types of cancer
        • Cons are it isn't 100% effective, it can cause bad side effects and it doesn't protect against STDs
      • Oestrogen can be used to prevent the release of an egg, if it is taken everyday to keep the level permanently high, it inhibits the production of FSH and after a while egg development and production stop
    • Increased fertility
      • if FSH are too low to cause the eggs to mature, this means that no eggs are released and woman cant get pregnant
        • The hormones FSH and LH can be injected to stimulate the egg release in the ovaries
          • It helps a lot of woman to get pregnant when previously they couldnt
          • It doesn't always work, it can be expensive and too many eggs can cause multiple pregnancy


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