Smoking

• Nicotine:

  • Increase heart rate and blood pressure
  • makes person high; addictive
  • increases risk of blood clots in arteries, leading to increased risk of coronary heart disease
• Carbon monoxide:

  • Reduces ability of blood to transport oxygen
  • Binds irreversibly to haemoglobin, forming carbohaemoglobin, so less oxygen binds to harmoglobin, less aerobic respiration occurs, releasing less energy for growth
• Tar:

  • Increased risk of lung cancer
  • Increased risk of chronic bronchitis and emphysema
  • paralyses cilia lining air passages, making cilia cells stuck
• What is chronic bronchitis?

  Prolonged exposure to smoke -> inflammed linings of bronchus

  -> secreting excessive mucus and bronchi is blocked so air cannot pass through

  -> causes person to persistently cough to clear air passages, increase risk of lung infection
• What is emphysema?

  • Persistence and violent coughing breaks down walls between alveoli and lungs
  • One-cell thick wall breaks and decrease surface area for gaseous exchange in lungs
• What is lung cancer ?

  Uncontrolled division of cells producing outgrowths/lumps of tissues
• Pathway of nicotine to brain

  1. Nicotine in alveoli dissolves in layer of moisture and diffuse into blood capillary
  2. Transport back to heart by pulmonary vein
  3. blood with nicotine forced out of heart into aorta
  4. transported to brain by coronary artery branching off from aorta
• Pathway of tobacco to fetus blood (has same points as nicotine -> brain except last one)

  1. Pharynx -> larynx -> trachea -> bronchi -> bronchioles -> alveoli (structure of how air flows into lungs)
  2. Diffuse into mother's blood capillary into fetus blood capillary at placenta(in uterus connected to fetus)