B1.2.2 Control in the Human Body

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09amion
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184181
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B1.2.2 Control in the Human Body
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2012-11-18 07:38:42
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GCSE Biology B1 Control Human Body
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Covers the control in the human body topic in Biology GCSE
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  1. What controls the menstrual cycle?
    Hormones made in the pituitary gland in the brain and in the ovary
  2. Why does the lining of the womb build up each month?
    So that it would be ready to support the developing embryo if an egg was fertilised
  3. What is a contraceptive?
    Something that reduces the risk of you getting pregnant (conceiving)
  4. What is the difference between the mixed pill and the progesterone-only pill?
    The mixed pill contains oestrogen and progesterone, which prevents ovulation, inhibits FSH secretion, stops the build up of lining of the uterus, etc. The progesterone-only pill doesn’t stop ovulation, it is not quite as effective but it has fewer side effects
  5. Define oral contraceptive
    A pill taken by mouth that reduces the risk of pregnancy
  6. Define fallopian tube
    The tube between the ovary and the uterus that the egg travels along (where conception usually takes place)
  7. Define fertility drug
    A drug which stimulates the ovaries to produce ripe eggs
  8. Define in vitro fertilisation 
    In humans this means combining the egg and sperm in a Petri dish, so fertilisation takes place outside the body
  9. How artificial female hormones can be used to a prevent unwanted pregnancies?
    The hormones in contraceptive pills can be used to prevent the release of eggs, stop the build up of the lining of the uterus, etc., so that pregnancy cannot take place
  10. Explain how artificial female hormones can be used to help people overcome infertility
    Fertility drugs can be used to stimulate the production of eggs in the ovary so that infertile couples can become pregnant, either naturally, once the eggs have been produced or using IVF
  11. Why is homeostasis important?
    Homeostasis is important because cells of the body need a constant environment in which to work properly
  12. What do your kidneys control?
    The kidneys control the balance of water and mineral ions in the blood - it gets rid of excess ions from the blood which comes out as urine
  13. What is the ideal body temperature?
    37 °C
  14. What would happen to your blood sugar level if you ate a packet of sweets?
    It would go up
  15. Why is it important to control water levels in the body?
    To stop too much water moving in or out of cells, damaging and destroying them
  16. Why is it important to control the body temperature?
    Because the enzymes work best at 37 °C
  17. Why is it important to control sugar (glucose) levels in the blood?
    Because blood sugar that is too high or too low causes problems in the body
  18. Describe how running affects water balance
    You lose water through sweating
  19. Describe how running affects ion balance
    You lose salt through sweating
  20. Describe how running affects your temperature
    Temperature goes up with exercising
  21. It is much harder to run a marathon in a costume than in running clothes. Explain why this is
    Sweating cools you down and helps to keep the body temperature down – a costume makes you sweat more (as you get hotter), which means you lose more water – but also makes it harder for sweat to evaporate (so you don’t cool so effectively). Also, a costume is heavy so it’s harder work to run
  22. What are hormones produced and secreted by?
    Glands
  23. What do hormones travel in?
    Blood (carried in blood plasma)
  24. What are hormones?
    Hormones are chemical messengers which travel in the blood to activate target cells
  25. What does the pituitary gland produce?
    Many important hormones including FSH and LH which are involved in the menstrual cycle
  26. What do ovaries produce?
    Oestrogen and progesterone which are involved in the menstual cycle and causes changes at puberty
  27. Do hormones have generally long-lasting effects or short-lasting effects
    Relatively long-lasting effects
  28. What do hormones control?
    They control things in organs and cells that need constant adjustment
  29. Hormones affect target cells... What does this mean?
    It means that they only affect particular cells in particular places
  30. Which is quicker for carrying messages: hormones or nerves?
    Nerves
  31. What are the main differences between nerves and a hormones?
    • Nerves are very fast whereas hormones are slower
    • Nerves act for a very short time whereas hormones act for a long time
    • Nerves act on a precise area whereas hormones act in a more general way
  32. What is the menstrual cycle?
    The monthly release of an egg from a woman's ovaries, and the build-up and breakdown of the protective lining in the uterus (womb)
  33. During the menstrual cycle, the hormone FSH stimulates the production of oestrogen in the ovaries. Describe how this response is carried out
  34. What happens on day 1 of the menstrual cycle?
    The bleeding starts and uterus lining breaks down for about 4 days
  35. What heppens from day 4 to day 14 of the menstrual cycle?
    The lining of the uterus builds up again into a thick spongy layer of blood vessels, ready to receice a fertilised egg
  36. What happens at day 14 of the menstrual cycle?
    An egg is developed and then released from the ovary
  37. What happens from day 14 to 28 of the menstrual cycle?
    The wall is mantained from from day 14 to 28. If no fertilised egg has landed on the uterus by day 28, the spongy lining starts to break down again and the whole cycle starts again
  38. Which 3 hormones is the menstrual cycle controlled by?
    FSH, oestrogen and LH
  39. What does FSH do?
    Causes an egg to mature in one of the ovaries and stimulates the ovaries to produce oestrogen
  40. What gland produces FSH?
    Pituitary gland
  41. What gland produces Oestrogen?
    Ovaries
  42. What does oestrogen do?
    Causes pituitary to produce LH and inhibits the further release of FSH
  43. What does LH do?
    Stimulates the release of an egg at around the middle of the menstrual cycle
  44. How can oestrogen be used in reducing fertility?
    It can be used to prevent the release of an egg, so it can be used as a method of contraception
  45. How can progestrone be used in reducing fertility?
    By stimulating the production of thick cervical mucus which prevents sperm getting through and reaching an egg
  46. What type of contraceptive is the pill?
    Oral
  47. When was the version of the pill made and what hormones did it contain?
    1950s and contained high levels of oesthrogen and progesterone (known as combined oral contraceptive pill)
  48. To prevent the release of an egg through oestrogen, do you lower the level or keep it high?
    You keep it permantently high by taking it everyday which inhibits the production FSH and after a while, egg development and production stop
  49. Why do pills now have lower doses of oestrogen?
    There were side effects like blood clots and so the dose was lowered to have fewer side effects
  50. What are the pros of taking a pill to reduce fertility?
    • The pill's over 99% effective at preventing pregnacy
    • It reduces the risk of getting some types of cancer
  51. What are the cons of taking a pill to reduce fertility?
    • It isn't 100% effective - there' still a slight chance of pregnancy
    • It can cause side effects like headaches, nausea, irregular menstrual bleeding and fluid retention
    • It doesn't protect against STDs
  52. What is good about the progesterone-only pill and what is bad?
    It has fewer side effects however, it's not as effective
  53. What does it mean if women have low levels of FSH?
    Means that no eggs are relased anf the women can't get pregnant
  54. What are the pros of injecting FSH and LH into women to increase fertility?
    It helps a lot of women get pregnant when they previously couldn't
  55. What are the cons of injecting FSH and LH into women to increase fertility?
    • It doesn't always work, some women may do it many times which can be expensive
    • Too many eggs could be stimulated, resulting in unexpected pregnancies (e.g. twins)
  56. Why do women have FSH and LH injected into them?
    Too increase fertility by causing the eggs to mature and be released
  57. What does FSH stand for?
    Follicle-Stimulating Hormone
  58. What does LH stand for?
    Luteninising Hormone
  59. What does IVF stand for?
    In vitro fertilisation
  60. What does IVF involve?
    Collecting eggs from the woman's ovaries and fertilising them in a lab using the men's sperm. These are then grown into embryos and once the embryos are tiny bals of cells, 1 or 2 of them are transferred to the woman's uterus to improve the chance of pregnancy.
  61. In IVF, why is FSH and LH given before egg collection?
    To stimulate egg production so more then 1 egg can be collected
  62. What are the pros of IVF?
    Fertility treatment can give an infertile couple a child
  63. What are the cons of IVF?
    • Some women have a strong reaction to the hormones - e.g. abdominal pain, vomiting, dehydration
    • There have been reports of an increased risk of cancer due to the hormonal treatment (though others have reported no such risk - so position isn't really clear at the moment)
    • Multiple births can happen if more then 1 embryo grows in to a babie - these are risky for the mother and babies (there's a higher risk of miscarriage, stillbirth...)
  64. What is homeostasis?
    It means all the functions in your body which try to maintain a 'constant internal environment'
  65. Some ions are lost in...
    Sweat
  66. What does the gut do?
    Puts glucose into blood from foods containing carbohydrates
  67. What removes glucose from the blood?
    The normal metabolism of cells
  68. If you do lots of exercise, lots more......is removed from the blood by the metabolism of cells
    Glucose
  69. What does the hormone insulin do?
    It helps maintain the right level of glucose in your blood, so your cells get a constant supply of energy
  70. What 4 things does your body need to keep at the right level?
    Ioncontent, sugar content, water content and temperature
  71. How is water taken in to the body?
    Through food and drink
  72. How is water lost from your body?
    • Through skin as sweat
    • Via the lungs in breath
    • Via the kidneys as urine
    • (Also, some water is lost in faeces)
  73. How much do you sweat on a cold day, when you're not exercising
    Not much
  74. How much urine will you produce on a cold day, when you're not exercising
    You will produce more urine, which will be pale (since the waste carried in the urine is more diluted)
  75. How much urine will you produce on a hot day, when you are exercising?
    You will produce less urine but it will be more concentrated (deeper colour)
  76. How much do you sweat on a hot day, when you are exercising and how else could you lose water (apart from sweat)?
    You would sweat a lot and you could lose water through your breath because you breathe faster 
  77. What part of your body senses blood temperature?
    The brain
  78. Why is it important that human body temperature is kept at 37 degrees?
    This is the optimal temperature of most enzymes in your body
  79. What effect does oestrogen have on the release of FSH?
    It inhibits it
  80. On a hot summer day Katie is running in the park, while Colin is sitting at home reading a book. Will Colin or Katie have more concentrated urine and why?
    Katie. She will have more concentrated urine than Colin because she will be losing more water through sweating (and breathing)
  81. The bloodstream usually transports hormones from the glands to their......organs.
    Target
  82. What does the adrenal glands produce?
    Produces adrenaline which prepare the body for rapid activity by increasing the heart rate and level of sugar in the blood and diverting blood to muscles and brain
  83. What does the throid gland produce?
    Produces thyroxine which controls the rate of metabolism
  84. What does the pancreas produce?
    Insulin which controls the blood sugar levels
  85. What does the testes produce?
    Produces testosterone which causes the changes at puberty and stimulates sperm production
  86. What part of the brain controls the pituitary gland?
    Hypothalamus

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