2.47 understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart disease

  • Nicotine is an addictive substance found in tobacco
  • Carbon monoxide reduces the amount of CO2 carried in the blood
  • Tar and other chemicals in tobacco smoke can cause lung cancer, bronchitis, emphysema, diseases of the heart and blood vessels

From the GCSE Edexcel 2013 Biology textbook

  • Nicotine and carbon monoxide in tobacco smoke raises heart rate – leading to higher blood pressure. They can lead to heart attacks or strokes
  • Nicotine and carbon monoxide reduce the ability for blood to carry oxygen – carbon monoxide combines with the haemoglobin (oxygen carrier in red blood cells) so there is less space for the oxygen to be carried around the body as oxyhaemoglobin. This leads to the person being breathless, especially when undertaking physical activity
  • Tar in smoke damages cilia on the surface of bronchi and bronchioles. When cilia are damaged, there is a buildup of mucus that is not removed, so the bacteria that are normally removed from the mucus stay in the lungs. This leads to a greater risk of infections and can cause mutations in lung cells
  • Emphysema is a condition which makes the alveoli less elastic and sometimes the walls begin to break down. One large air sac has a much smaller surface area than many small ones, this reduction in surface area means the person does not obtain enough oxygen.

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