Problems of, and solutions to a changing environment

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  • A chemical substance that affects the central nervous system, causing changes in psychological behaviour, as well as addiction


  • Block pain impulses and are largely available
  • If nerve impulses are blocked => no sensation => morphine molecules are very good at this


  • Create hallicinations and distort sense of perception => normal nerve impulse is interfiered with


  • Slow down your responses and increase your reaction times to a physical/mental situation
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Problems associated with smoking

  • Nicotine is an addictive drug => smokers become dependant on it
  • Tar as a carcinogen can cause mutations in the cells of the throat and lungs => could result in lung cancer/throat cancer
  • Carbon monoxide reduces the oxygen in blood => gets converted to carboxyhaemoglobin
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Problems associated with alcohol abuse

  • Blurred vision => when highly intoxicated, balance is effected => blurry vision
  • Slowing of reactions => Alcohol is a depressant and slows down brain activity 
  • Brain damage => Is associated to significant brain lesions => causes permanent brain damage
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How pathogens are spread

  • Water: when in contact with contaminated water, pathogens are spread => why pools are treated to kill bacteria with chlorine
  • Food: eating food contaminated with pathogens => can cause food poisoning
  • Airborne: sneezing => producing a fine mist of water droplets containing millions of bacteria
  • Contact: touching a contaminated surface => e.g athlete's foot is spread widely by swimming baths
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How we can protect ourselves from pathogens

  • Chemical defense: our eyes produce Iysozymes that kill bacterial microorganisms on surface of eye, stomach producing HCl to kill off bacteria
  • Physical defense: mucous traps bacteria before it enters the the lungs, skin is quick in recovery (releases PAF hormone and plugs wounds)
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