GCSE - Biology - Homeostatis and Response

• If the Thyroxine levels are too high then...

  the pituitary gland releases Thyroid Stimulating Hormone
• Genetic testing raises ethical issues as it...


  could lead to the selection of preferred characteristics
• IVF often results in...

  unused embryos which have to be destroyed
• Some women on IVF have a...

  strong reaction to the hormones so it is physically challenging
• What is the average success rate for IVF in the UK?

  26%
• FSH and LH are given before egg collection to...


  increase egg production do more than one can be collected
• Once the embryos are tiny balls of cells...


  one or two of them are transferred into the uterus to improve he chances of pregnancy
• The fertilised egg is grown into an embryo in a...

  laboratory incubator
• What is the process called in which the sperm is injected directly into he egg if a mans sperm count is low?

  Intra-Cytoplasmic Sperm Injection
• IVF involves collecting eggs from the ovaries and fertilising them in a...

  lab with the mans sperm
• Cons of fertility drugs is that they are...

  expensive, not always effective and too many eggs could be released resulting in unexpected twins, triplets etc...
• These hormones can be given to women as...

  fertility drugs to stimulate ovulation
• If women have FSH that are too low then...

  no eggs will mature
• What is the only way to make sure the sperm and egg never meet?


  Abstinence
• Natural Methods' involve finding out when...

  the woman is most fertile and avoiding sex on these days (if people think barrier methods are unnatural)
• Sterilisation in a man involves cutting or tying the...

  sperm duct
• Sterilisation in a woman involves cutting or tying the...

  Fallopian tubes
• Spermicide alone is only about...

  70-80% effective
• It has to be used with a...

  spermicide to kill sperm
• A diaphragm is a small plastic cup that fits over the...


  cervix (barrier)
• Condoms are the only form of contraception that prevent...


  STDs because they act as a barrier
• Copper IUDs


  prevent sperm from surviving in the uterus
• Plastic IUDs...


  release progesterone
• An IUD is a T-shaped device inserted into the...

  uterus
• A contraceptive injection lasts...

  2-3 months
• An Implant lasts...

  three years
• The implant releases...

  progesterone
• The contraceptive implant is inserted under...

  the skin of the arm
• Its stuck to the skin and lasts...

  one week
• The contraceptive patch contains...

  oestrogen and progesterone
• The pill contains oestrogen and progesterone but...


  can cause headaches and nausea and doesn't protect against STDs (but is 99% effective)
• Progesterone reduces fertility because it...


  produces a thick mucus which prevents sperm getting through
• Oestrogen can prevent the release of an egg because it...

  inhibits the production of FSH so no eggs mature
• Progesterone inhibits the release of...

  FSH and LH
• When the progesterone levels fall...


  the lining breaks down
• Progesterone maintains the ...

  lining of the uterus
• Progesterone is produced in the...

  ovaries by the remains of the follicle
• LH stimulates the release of...

  an egg at day 14
• LH is produced by the...

  Pituitary Gland
• Oestrogen stimulates the release of...?

  LH - which causes the release of the egg and inhibits the release of FSH.