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OCR Nationals Ideas in Context Exam 2012 B4 C4 P5

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    Hi there, i have got an Ideas in Context Exam next week and my teacher has not given us any sheets or questions that might come up in the exam so i was just wondering whether any of you could help me out with this please i used this website last year in year 10 and found it really helpful as i got a B in the exam thankyou
    The Exam is on..

    Hypothermia (B4)
    Dangers and delights of Chlorine and Bromine (C4)
    The National Grid (P5)

    i would be really grateful if someone could help me out here, thankyouu
    chloe x
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    Hi Chloe,

    Here are some questions and answers I have been working on for the biology part. I am not sure that they are all right - if anyone wants to correct me or add anything then please do!!! But someone did this last year and I found it really helpful too! I will post the C4 and P5 stuff when I've worked it out!!

    What is hypothermia?
    Hypothermia is a condition where the core body temperature drops below that required for normal reactions and body functions.

    What is the normal range for a core body temperature?
    From 36.5 - 37.5 degrees Celsius

    Explain what is meant by core body temperature
    Core body temperature is the exact temperature at which all the functions of the human body can go ahead with optimal efficiency.

    What is meant by the term temperature regulation (thermoregulation)
    A normal, healthy human is able to maintain a constant body temperature despite the temperature of the environment.

    Why is temperature regulation important in humans?
    This is because enzymes, which are crucial in keeping your body functioning, are most efficient at catalysing reactions at this temperature.

    What parts of the body controls temperature regulations?
    The brain


    What are receptors?
    They can detect changes (stimuli) in the environment.

    What are effectors?
    An effecter is any part of the body that produces the response to a stimuli

    What is negative feedback?
    Negative feedback is a physiological response that counteracts a change to the body's homeostatic parameters.

    What is a control centre?
    A control centre is in the brain – when the receptor senses a stimulus, it sends information to the control centre in the brain which determines an appropriate response to the stimulus. It then sends signals to an effector – which can be muscles, organs or other structures. After receiving the signal, a change occurs to correct the deviation by either positive or negative feedback.



    In full sentences explain how negative feedback maintains core body temperature
    Negative feedback ensures that, in any control system, changes are reversed and returned back to the set level. So if a person is too cold, the receptors in the body – including the blood vessels - will act as the receptors and relay the message to the brain that the body is too cold. The brain then sends a message to the blood vessels and muscles, telling them to restrict and to shiver which helps the body to keep heat in and to warm itself – to try to get the body back to normal temperature. It will also make the skin have ‘goosebumps’, making the small hairs on the skin stand up, acting as a layer of insulation to keep the heat in. If the person is too hot, the opposite will occur – the receptors will send the message to the brain which will in turn tell the effectors to dilate the blood vessels so that they are closer to the skin’s surface and heat will be lost through the skin, bringing the body’s core temperature down. Sweat will also be produced which evaporates on the skin, also cooling the body.

    Why is temperature important for enzyme function
    Enzymes need to be at a specific constant temperature to work at their optimum

    What is vasoconstriction?
    When blood vessels contstrict, the blood flow is reduced

    What is vasodilatation?
    When blood vessels dilate, the blood flow is increased.

    Describe the processes that lead up to vasoconstriction
    Receptors in the blood vessels send a message to the brain to say that the body is too cold, or that blood pressure is too low. This would then relay a message to the effectors in the vessels telling them to constrict which would make the blood pressure increase, and the body keep in more warmth.

    During moderate hypothermia lips, ears, fingers, toes, can appear pale. Explain why
    This is because the body diverts the blood away from the extremities so that it can flow closer to the heart and keep the heart and other organs warmer.

    What is the function the shivering?
    Relaxes and contracts muscles really fast causing body to shake/shiver in an attempt to warm it up and create blood flow to those areas.


    Suggest how a person with mild hypothermia should be treated
    Move the person somewhere warm. Change them out of wet clothing. Wrap them in warm clothing. Give them warm drinks, but not alcohol. Give them food that is rich in carbohydrates.

    Suggest how a person with moderate hypothermia should be treated

    The person would need proper medical help. In the meantime you should take off any wet clothes, warm the body core first, including chest, groin, neck and head before warming the extremities. Warming the arms and legs first causes cold blood to rush back to the heart and organs which could make things worse. You can also use a heated blanket or pad, hot water bottles, warm bottles of water. Share your own body heat with the person by wrapping yourself up with him or her in a blanket or sleeping bag. Hug the person trying to make as much body contact as possible. Give the victim warm liquids to drink but nothing containing alcohol or caffeine as they both interfere with the body’s ability to regulate its temperature.

    Suggest how a person with severe hypothermia should be treated
    Exactly the same as above – but make sure to get expert medical help as the person is at extremely high risk of having a heart attack. In a hospital they may try active core rewarming using intravenous warmed fluids (Putting warm liquids directly into a person’s blood stream via a drip), or using warm air inhalers, or by putting the person onto a heart lung machine.

    Explain how alcohol impairs the temperature regulation
    While alcohol may make us feel hotter, it actually aids in decreasing core body temperature. Normally when we feel cold, it is because blood has flowed from our skin into the organs to keep our core body temperature warm. After alcohol consumption, our blood vessels dilate and blood flows into the skin, giving us that warm feeling and making our faces flush, but means that the body loses heat more quickly.

    Explain why people with hypothermia should not be given alcoholic drinks
    Alcohol should not be given to someone with hypothermia because it will cause the blood vessels in the arms, legs and throughout the surface of the skin to dilate too quickly, causing the body to lose heat.

    Why is it important that warm clothing should be worn around the head and neck?
    Most core body heat escapes from the head, neck and feet

    What are carbohydrates?
    Carbohydrates are starchy foods such as bread and pasta that are a high source of energy and slow burning sugars.

    In terms or their ability to release energy, why are carbohydrates recommended for a person with hypothermia?
    Carbohydrates are recommended for a person with hypothermia because it helps them have an instant energy boost and the body needs energy to generate heat.

    In terms or their ability to release energy, why are fats recommended for a person with hypothermia?
    Fats will give the person longer lasting energy to help keep the body warm.

    Why does the pulse and breathing rate decrease significantly in a person with severe hypothermia?
    Your core body temperature is low therefore slowing down your body's circulation and slowing down your heart rate as the blood vessels constrict.

    What effect do wet clothes have on a person's ability to maintain their core body temperature?
    Your body uses its energy to warm up the wet clothing and therefore is not using the energy to maintain its core temperature

    Why is the removal of wet clothes recommended for a person with hypothermia?
    This is so that the body can focus on using its energy to warm itself up and not the surrounding wet clothing.

    Suggest reasons why shivering stops during sever hypothermia
    The body doesn't have enough energy and starts to shut down. Parts of the brain ceases to function and loses the ability to control its muscles. When someone has severe hypothermia, they may look as if they are dead – their pulse will be extremely weak and they will not move at all.
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    have you got any information about the dangers and delights of chlorine and bromine packing as i dont understand it!
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    and my exams tomoz!!!
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    anyone got any questions + answers for the chemistry + physics

    it will be much apprechiated thank you

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Updated: May 30, 2012
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