4.6.5

Lung Disease

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Overview of Lung Disease

Lung disease affects the ability of the lungs to exchange gases over their surface. This can be direct tissue damage or a reduced ability to ventilate.

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Diseases

  • Lung diseases can cause issues with gas exchange and ventilation. Diseases include:
    • Asthma.
    • Pulmonary fibrosis.
    • Tuberculosis.
    • Emphysema.
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Causes

  • Gas exchange problems are caused when the exchange system is damaged.
  • The causes of these problems can include:
    • Decreased surface area.
    • Increased diffusion distance.
    • Decreased concentration gradient.
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Symptoms

  • Symptoms of gas exchange or ventilation issues include:
    • Coughing mucus or blood.
    • Faster, shallower breathing.
    • Blood oxygen saturation readings below 90%.
    • Fatigue.

Effects of Lung Disease

Different lung diseases have different effects on gas exchange and/or ventilation in the respiratory system. These effects include:

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Emphysema

  • Emphysema is caused by smoking or air pollution.
  • Dirt and bacteria become trapped in the alveoli which damages the alveoli walls.
  • The alveoli provide a large surface area for gas exchange.
  • Damage to the walls decreases the surface area and rate of gas exchange declines.
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Asthma

  • Asthma increases the production of mucus by the epithelial cells.
  • The increased mucus increases the length of the diffusion distance.
  • The greater diffusion distance decreases the rate of gas exchange.
  • An asthma attack also causes the smooth muscle in the bronchioles to contract. This makes it difficult to breathe.
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Tuberculosis

  • Tuberculosis bacteria can infect the lungs, damaging the lung tissue.
  • The cells of the immune system can also damage the lungs.
  • The damaged lungs lead to a decreased tidal volume.

Jump to other topics

1Principles of Science I

1.1Structure & Bonding

1.2Properties of Substances

1.3Cell Structure & Function

1.4Cell Specialisation

1.5Tissue Structure & Function

1.6Working with Waves

1.7Waves in Communication

2Practical Scientific Procedures and Techniques

3Science Investigation Skills

4Principles of Science II

4.1Extracting Elements

4.2Relating Properties to use of Substances

4.3Organic Chemistry

4.4Energy Changes in Industry

4.5The Circulatory System

4.6Ventilation & Gas Exchange

4.7Urinary System

4.8Cell Transport

4.9Thermal Physics

4.10Materials

4.11Fluids

5Contemporary Issues in Science

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