B1.1 - Keeping healthy

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  • Created by: Emily_O
  • Created on: 27-09-13 22:59

Diet and exercise

  • A healthy diet contains the right balance of the different foods you need and the right amount of energy
  • A person is malnourished if their diet isn't balanced and this may lead to a person being over or under weight
  • An unbalanced diet may also lead to deficiency diseases or conditions such as Type 2 diabetes
  • A person loses mass when the energy content of the food taken in is less than the amount of energy expended by the body. Exercise increases the amount of energy expended by the body
  • The rate at which all chemical reactions in the cells of the body are carried out (the metabolic rate) varies with the amount of activity you do and the proportion of muscle to fat in your body. It may be affected by inherited factors which also affect our health (e.g. cholesterol level)
  • People who exercise regularly are usually healthier than people who take little exercise
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Pathogens and disease

  • Microorganisms that cause infectious disease are called pathogens such as viruses and bacteria
  • Bacteria and viruses reproduce rapidly inside the body
  • Bacteria can produce toxins which make you feel ill
  • Viruses damage the cells in which they reproduce, making you feel ill
  • Ignaz Semmelweis recognised the importance of hand-washing in preventing the spread of infectious diseases in hospitals
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Defense mechanisms

The body has different ways of protecting itself against pathogens:

  • White blood cells help to defend against pathogens by ingesting them; producing antibodies which destroy particular bacteria or viruses; and producing antitoxins which counteract the toxins released by pathogens
  • The immue system of the body produces specific antibodies to kill a particular pathogen which leads to immunity from that pathogen
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Using drugs to treat disease

  • Some medicines, including painkillers, help to relieve the symptoms of infectious disease, but don't kill the pathogens
  • Antibiotics cure bacterial disease by killing infectious bacteria inside the body. They can't be used to kill viral pathogens which live and reproduce inside cells
  • Many strains of bacteria including MRSA have developed resistance to antibiotics as a result of natural selection. To prevent further resistance arising it's important to avoid overuse of antibiotics
  • Mutations of pathogens produce new strains which antibiotics and vaccinations may no longer be effective against. The new strain will spread rapidly as people aren't immune to it and there is no effective treatment
  • The development of antibiotic-resistant strains of bacteria necessitates the development of new antibiotics
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  • People can be immunised against a disease by introducing small quantities of dead or inactive forms of the pathogen into the body (vaccination)
  • Vaccines stimulate the white blood cells to produce antibodies that destroy the pathogens
  • This makes the person immune to future infections by the microorganism as the body can respond by rapidly making the correct antibody in the same way as if the person had previously had the disease
  • We can use vaccinations to protect against both bacterial and viral pathogens
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