B2 KEEPING HEALTHY

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  • Created by: abic1
  • Created on: 09-03-16 18:16
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  • B2- KEEPING HEALTHY
    • MICRO ORGANISMS AND DISEASE
      • include bacteria, viruses and some fungi
      • can cause infectious diseases
      • symptoms are caused by cell damage or toxins
      • effects that an infection has on the body are called symptoms
      • toxins can either damage the material holding a cell together or poison cells
      • bacteria reproduce by making copies of themselves
      • bacteria need nutrients, moisture and warmth to grow
      • viruses need other cells to reproduce
      • every microorganism has a reproduction period
      • twice as many microorganisms are produced at the end of each reproduction period
    • THE IMMUNE SYSTEM
      • the immune system fights off invading microbes
      • white blood cells fight off infections
      • white blood cells detect foreign bodies and engulf and digest them
      • white blood cells have receptors that recognise certain antigens
      • antigens are substances that trigger immune responses
      • white blood cells produce antibodies which match to a certain antigen
      • antibodies can kill bacteria directly
      • antibodies can mark antigens so other white blood cells can engulf them
      • antibodies can bind to and neutralise viruses and toxins
      • some white blood cells stay in the body when the infection has gone these are called memory cells
      • memory cells recognise antigens quickly and reproduce to fight the infection before you become ill
      • killing microorganisms before you become ill is called immunity
    • VACCINATION
      • injecting dead or inactive microorganisms
      • they still carry antigens so antibodies are produced to attack them
      • body produces memory cells that stay in the blood
      • if live microorganisms then appear, the memory cells can fight them off
      • epidemics can be prevented by vaccination
      • if people aren't vaccinated, diseases will spread quickly
      • if most people are vaccinated, fewer people can pass diseases on
      • vaccines are never safe for everyone
      • genetic differences mean people have different reactions
    • ANTIMICROBIALS
      • chemicals that inhibit the growth of microorganisms
      • help clear up infections
      • antibiotics are a type of antimicrobial
      • antibiotics don't kill viruses
      • random mutations can mean microorganisms become less affected by antimicrobials
      • the gene for resistance can be passed on
      • superbugs are resistant to most known antimicrobials
      • the more often antimicrobials are used the bigger the problem of resistance
    • HOMEOSTATIS
      • balancing the inputs and the outputs to maintain a constant internal environment
      • cells need the right conditions to function properly
      • automatic control systems regulate the internal environment
      • nervous and hormonal systems are automatic control systems
      • receptors processing centres and effectors make up automatic control systems
      • negative feedback counteracts change
      • the receptors detect changes in the environment
      • effectors produce responses as long as they are stimulated by the processing centre
      • automatic response
    • HEART RATE AND BLOOD PRESSURE
      • heart rate is number of times the heart beats per minute
      • heart rate is measured in BPM
      • pulse rate is number of times an artery pulses each minute
      • when the heart contracts blood is forced out the heart
      • when the heart muscle contracts, blood pressure increases
      • when the heart relaxes the heart fills with blood
        • if the fatty deposits break through the artery, blood clots are formed which can clot the artery
          • blocked arteries stop blood flowing to the heart, meaning no oxygen gets to the heart which results in a heart attack
      • when the heart is filled with blood, blood pressure decreases
      • normal measurements are given as a range as individuals vary
      • high blood pressure increases the risk of heart disease
      • fatty deposits build up in damaged areas of arteries which restricts blood flow and causes high blood pressure
    • HEART DISEASE
      • linked to lifestyle factors
      • genetics can put people at higher risk
      • poor diet, stress, smoking, drinking alcohol and using drugs can contribute
      • cholesterol makes fatty deposits in damaged arteries which causes clots and blood pressure to increase
      • food high in saturated fat and salt increases blood pressure
      • caused by high blood pressure
      • carbon monoxide and nicotine increases the risk of heart disease
      • if the heart doesn't get enough oxygen it will stop
      • stress, drinking and using drugs increases heart rate, which increases blood pressure
    • CONTROLLING WATER CONTENT
      • inputs are what water is gained by such as food drinks and respiration
      • outputs are how water is lost breathing and sweating
      • kidneys help balance substances in the body
      • kidneys filter small molecules including water, salt, sugar and waste from the blood
      • kidneys reabsorb all the sugar, and as much salt and water is needed
    • DRUG TRIALS
      • every new drug has to be tested to make sure it is safe and that it works
      • developed using human cells
      • drugs help to fight diseases
      • tested on at least two different species of live mammal then human volunteers
      • testing is stopped if the drug causes serious problems or if it is not effective
      • tests on human volunteers are called human trials
      • tested on healthy people to make sure there are no bad side effects, as ill people are more vulnerable
      • placebos are also used to give a comparison of the group given the drug and the group given the placebo
      • placebos are not used if the patient is seriously ill as it is unethical
      • if the drug works the people who had the placebo will not improve as much as those who had the drug
      • in blind trials only the patient doesn't know if they have the drug or the placebo
      • in double-blind trials both the doctors and patients don't know if they have the placebo or the drug
      • in open-label trials both the doctors and patients are aware of the treatment used as it cant be hidden, eg exercise or a drug

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