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Keeping Healthy Revision

Keeping Healthy Revision. Natural Barriers. Skin Sweat Tears Stomach acid. Infection. Micro-organisms increase in numbers rapidly. The symptoms of a disease are caused by the micro organisms or their toxins. The body has an immune system to fight infection. White Blood Cells.

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Keeping Healthy Revision

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  1. Keeping Healthy Revision

  2. NaturalBarriers Skin Sweat Tears Stomach acid

  3. Infection • Micro-organisms increase in numbers rapidly. • The symptoms of a disease are caused by the micro organisms or their toxins. • The body has an immune system to fight infection.

  4. White Blood Cells • Some white blood cells ‘eat’ invading micro organisms (phagocytosis). • Some white blood cells produce antibodies that stick to invading micro organisms. • Each antibody will be specific to a particular micro organism eg chicken pox. • Once produced, the white blood cells remember the micro organism and kill it very quickly next time it invades.

  5. Vaccines • Vaccines inject a small amount of ‘safe’ micro organisms causing the body to produce antibodies. • The White blood cells remember the ‘safe’ version and attack the disease causing micro organism when it invades giving immunity. • Vaccines can produce side effects in some and so are never totally safe. • Some micro organisms (eg influenza, HIV) mutate (change) so quickly that the antibodies don’t recognise them. This makes it difficult to get immunity • Some organisms eg AIDS damage the immune system making it difficult to get immunity.

  6. Vaccination (cont) • Need a lot of people to be vaccinated to prevent epidemics (herd immunity). • Some people may not wish to risk the side effects (MMR). This may prevent herd immunity being achieved.

  7. Antibiotics • Antibiotics kill bacteria but not fungi or viruses. • Bacteria can mutate and become resistant to the antibiotic. • We should therefore only use antibiotics when necessary and complete the course. • The resistant bacteria will survive better if we take too many antibiotics and kill all the competition

  8. Drug Testing • New drugs must be tested to make sure they are safe and effective. • This may involve animal trials. • Human trials involve ‘blind’ and ‘double blind’ trials, and placebos. • Ethical issues are involved with respect to animal testing and selecting people for trials.

  9. Heart Disease • Very common in the UK and industrialised countries. • Is caused by a build up of fatty deposits in the coronary arteries. • Lifestyle factors such as poor diet, smoking, stress and alcohol increase the chances of heat disease. • Regular, but not excessive, exercise reduces the chance of heart disease.

  10. Analysing Data • Distinguish between correlation and cause. • Assess critically whether studies are reliable. • Describe the relationship between 2 factors on a graph, such as increase, decrease, steady, uniform and proportional.

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