tissues in lungs

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  • Created by: Harpreet
  • Created on: 15-11-13 17:56
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  • Tissues in the lungs
    • the lungs
      • airways
        • trachea
        • bronchus
        • larger airways must be large enough- allow enough air to flow through without obstruction
        • they must also divide into smaller airways-to get to the alveoli
        • must be strong: to prevent them from collapsing when pressure inside is low
          • this low pressure happens during inhalation
        • narrowest airway leading to alveoli, virtually no cartilage
    • trachea and bronchi
      • have similar structure
        • onyl differ in size: bronchi is narrower than trachea
      • have thick walls that have several layers of tissue
      • most of the walls consist of cartilage
        • in the form of C rings in the trachea but is less regular in the bronchi
      • on the inside surface of the cartilage is a layer of glandular tissue, elastic fibres, connective tissue, smooth muscle + blood vessels
        • this is often called loose tissue
      • the inner lining is an epithelium layer that has two types of cell
        • ciliated epithelium
          • cells that have little projections
            • called cilia
              • these waft the mucus produced by the goblet cells up the trachea
                • so no toxic substances get into the lungs
                • the mucus is wafted to the back of the throat and then swallowed
        • goblet cells
          • these cells secrete the mucus
      • the main difference is that trachea has more regular cartilage
    • cartilage
      • plays a structural role: supports trachea + bronchi, holding them open.
        • this prevents them collapsing when the pressure inside is low during inhalation
      • does not form a complete ring: C shaped
        • why?
          • to allow flexibility when you move your neck so it is not constricted
          • also allows for the oesophagus to expand when food is swallowed
    • smooth muscle
      • can contract which constricts airways:makes lumen narrower
        • what is the effect of constricting the bronchioles?
          • Untitled
  • the lungs
    • airways
      • trachea
      • bronchus
      • larger airways must be large enough- allow enough air to flow through without obstruction
      • they must also divide into smaller airways-to get to the alveoli
      • must be strong: to prevent them from collapsing when pressure inside is low
        • this low pressure happens during inhalation
      • narrowest airway leading to alveoli, virtually no cartilage
  • bronchioles
    • larger bronchioles may have some cartilage but smaller ones have none
    • their walls are made mostly of smooth muscle and elastic fibres
  • they must be flexible; to allow movement
  • this is often called loose tissue
  • role of mucus
    • to trap tiny particles from entering the lungs
      • this may include pollen and bacteria
    • trapping any particles may reduce the risk of infection

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