SCIENCE2.3

• The Health of the Human Respiratory System


  There are various substances in the air that can cause damage to the human respiratory system
• Diseases of the human respiratory system

  • Emphysema
  • Bronchitis
  • Lung cancer
  • Asthma
• Emphysema


  • Cell wall of the alveoli is damaged
  • Surface area of the alveoli is reduced
  • Gas exchange is less efficient
• Bronchitis


  • Inflamed bronchial tubes with abundant mucus production
• Lung cancer


  • Uncontrolled cell division
  • Spreads to every organ of the body such as the liver and bones
• Asthma


  • Bronchial tubes become inflamed, swollen and narrow
  • It is difficult for air to enter and exit through the lungs
• Hazardous substances in polluted air

  • Sulphur dioxide
  • Nitrogen dioxide
  • Dust
  • Carbon monoxide
  • Bacteria and viruses
  • Asbestos
  • Pollen
  • Cigarette smoke
• Effects of hazardous substances on the respiratory system

  • Sulphur dioxide: Irritates the throat and damages lung tissue
  • Nitrogen dioxide: Irritates the throat and causes difficulty breathing
  • Dust: Settled on the alveoli and respiratory tract, causing difficulty breathing
  • Carbon monoxide: Competing with oxygen to combine with hemoglobin results in less oxygen content in the blood
  • Bacteria and viruses: Causes colds, coughs and pneumonia
  • Asbestos: Asbestos fumes are carcinogenic substances that cause lung cancer
  • Pollen: Stimulates the respiratory tract of asthmatics and can cause asthma attacks
  • Cigarette smoke: Tar is a carcinogenic substance that causes lung cancer