Lung Disease

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Asthma

When the bronchioles become inflammed and air ways become restricted 

Causes - 

  • Exposure to pollutions
  • May inherit 

Effects on the lungs/ gas exchange surfaces

  • Inflammation of epithelial cells and tissue lining of the bronchioles narrowing the lumen
  • Smooth muscle contracts in the bronchioles narrowing lumen
  • Mucus is secreted increasing the diffusion pathway reducing gaseous exchange
  • Decreases the ability for entry of air so lower differences in as concentrations meaning reduced diffusion

Treatment

Bronchiodilators - cause muscle to relax and the diameter to increase increasing gasesous exchange

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Fibrosis

When epithelial cell lining become thicker in respone to lung damage

Causes

  • Inhaling microscopic particles 
  • pollution 

Effect on lungs

  • Loss of elasticity due to fibre like scar tissue, so less stretch and recoil

Effect on gaseous exchange surface

  • Decreased ability to inflate or deflate lungs, reduced volume during ventilation meaning lower differences in gas concentrations = less o2 absorbed leading to a shortness of breath
  • Thickened airways means thicker diffusion pathway so longer diffusion pathway

Treatment - Increase amount of oxygen to increase 02 concentration in the lungs

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Emphysema

Causes

  • Smoking
  • Air pollutions 

Effect on the lungs

  • Loss of elastic fibres due to response to allergens cigarette smoke
  • WBC release elactase ---> elastin -  the connective tissue in the lungs. No stretch or recoil making ventilation more challenging
  • Breaks down the alveoli walls decreasing surface area for gaseous exchange. 

Effect of gaseous exchange suface

  • Decreased ability to inflate or deflate  lungs as lower differences in gas concentrantions
  • Less surface area for diffusion because of the break down or alveoli walls

Treatment - more oxygen to increase 02 concentrations in the lungs meaning maintain concentration gradient = faster rate of diffusion

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TB

Causes

  • Mycobacterium turberculosis

Effect on the lungs

  • Bacteria multiplies in the lung tissues - small lumps in upper part where O2 is greatest
  • Sets up imflammatory response of the immune system - sends macrophages to engulf and digest baacterium
  • Can cause formation of cavities

Effect on gaseous exchange

  • Formation of cavities decreases SA for gas exchange so less diffusion
  • Fluid and scarring makes the diffusion pathway longer meaning O2 takes longer to diffuse in and out of the lungs so less diffusion

Treatment  3 - 4 different Antibiotics perscribed for 6-9 months. Taken everyday and continued for the full course.

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