The effects of smoking

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  • Created by: Gemma
  • Created on: 06-05-13 18:38
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  • Effects of smoking
    • Cigarette smoke
      • Tar- containing carcinogens ( cancer causing chemicals
      • Carbon monoxide
      • Nicotine
    • Short term effects
      • Tar settles in the lining  of the airways and alveoli
        • Increases diffusion distance for oxygen for O2 entering the blood and CO2 leaving
      • Tar paralyses of destroys cilia  so they're unable to move the layer of mucus away and up to the back of the mouth
      • Tar stimulates the goblet cells and mucus-secreting glands to enlarge and release more mucus which collects in the airways
      • Bacteria and viruses become trapped in the mucus and are not removed. They can multiply and eventually a combo of mucus and bacteria may block the bronchioles
        • The presence of bacteria and viruses means that the lungs are more susceptible  to infection- smokers are more likely to catch diseases like influenza and pneumonia
      • Presence of chemicals in tar lying on the surface of the airway may cause an allergic reaction
        • This causes the smooth muscles in the walls of the airways  to contract. The lumen gets smaller and restricts the flow of air to the alveoli
    • Long term effects
      • Smokers cough- an attempt to shift bacteria-laden mucus that collects in the lungs.
        • It results from the irritation of the airways by the mucus and bacteria, as well as from the need to clear the airways in order to get air down into the alveoli
        • A constant cough means that the delicate lining of the airways and alveoli to become damaged. The lining will eventually be replaced by scar tissue which is thicker and less flexible. The layer of smooth muscle in the wall of the bronchioles thickens. This reduces the lumen of the airway and the flow of air is permanently restricted
      • Frequent infections caused by the presence of bacteria and viruses in the mucus will inflame the lining of the airways. This damages the lining- the layer of epithelium.. It also attracts white blood cells to deal with tha pathogenic microorganisms
        • In order for the white blood cells to make their way out of the blood into airways they release enzymes. These enzymes digest parts of the lining of the lungs in order to pass through into the air spaces. This damages the elastic tissue in the lining of the lungs.
          • The greatest effect is in the small bronchioles and alveoli. Loss of elastic tissue can reduce the elasticity of the alveolous wall.
            • As we exhale, the alveolous walls do not recoil to push air out.The bronchioles collapse, trapping air in the alveoli. This can cause the alveoli to burst as the pressure in the lungs increase.
    • Lung cancer
      • Benzopyrene- the most harmful cacinogenic compound in tar
      • Cacinogenic compounds lie on the delicate surface of the lungs. They then enter the cells of the lung tissue.
        • They enter the nucleus and have a direct effect upon the genetic material
          • Any change in the genetic material is a mutation. If the mutation affects the genes that control cell division,then uncontrolled division may take place.= cancer
            • Cancers often start at the entrance of the bronchi as the smoker his this fork in the airway and deposits tar.
      • Often takes 20-30 years to develop. A cancer may have been growing for years before it is discovered
    • Diseases associated with smoking
      • Chronic bronchitis
        • Inflammation of the lining of airways + damage to the cilia + the overproduction of mucus so the mucus collects in the lungs
        • Symptoms- irritation in the lungs, continual coughing, coughing up mucus that is often filled with bacteria and white blood cells.
        • Leads to an increase of lung infection.
      • Emphysema
        • Loss of elasticity in the alveoli which causes them to burst
        • The lungs have a reduced surface area as larger air spaces are formed.= less surface area for gaseous exchange
        • Symptoms- Short of breath especially when exerting themselves
        • Loss of elasticity makes it harder to exhale. In severe cases the breathing will become shallow and more rapid.The blood is less oxygenated and fatigue occurs
      • Chronic obstructive pulmonary disease
        • Combination of diseases- chronic  bronchitis, emphysema, asthma.
      • Lung cancer
        • symptoms- continual coughing, shortness of breath, pain in the chest, blood coughed up in the sputum


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