Exchange and Transport

• What are the 3 layers of cells that the oxygen has to pass through to the alveoli?

  • alveolar epithelium
  • basement membrane
  • capillary endothelium
• What is Fick's Law?

  Rate of diffusion-proportional-surface area x conc difference

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  distance
• What are adaptations of bronchi?

  • Reinforced with cartilage to keep the airway open
  • Smooth muscle can contract or relax to constrict or dilate the airway to change airflow
  • Elastic tissue contains elastic fibres with elastin that allows stretching and recoiling
  • Lined with ciliated epithelium cells and goblet cells
• What are the adaptations of small bronchioles?

  • No cartilage
  • Smooth muscle that can contract or relax to constrict or dilate the airway and change airflow
  • Elastic tissue contains elastic fibres with elastin that allows stretching and recoiling

  >The recoil helps breathing out
• What are the adaptations of alveoli?

  • Walls consist of one layer of squamous epithelial cells/one cell thick
  • Large surface area - large number of small air sacs which increases rate of gas exchange
  • Partially permeable
  • Good blood supply
  • Ventilation of air
  • Elastic fibres
• What are the adaptations of trachea?

  • Rings of cartilage keeps the airway open
  • Smooth muscle can contract or relax to constrict or dilate the airway and change airflow
  • Elastic fibres contains elastic fibres with elastin that allows stretching and recoiling
  • Lined with ciliated epithelial cells and goblet cells
• What do goblet cells produce?

  They produce mucus
• What do the cilia do?

  Move mucus and debris up and out of the airways
• Where is the smooth muscle found and whats its function?

  • Found in trachea, bronchi and larger bronchioles
  • Smooth muscle can contract without conscious control - resulting in allergic reaction
  • When is contracts is constricts the airways which makes the lumen narrower
• Where are the elastic fibres found and whats its function?

  • Found in walls of trachea, bronchi, bronchioles and alveoli
  • Help in the process of breathing out
  • When breathing out the elastic fibres are stretched- then fibres recoil to help force air out when breathing out
• Whats the function of cartilage?

  • Provides the strengthening and support
  • It consists of cells surrounded by complex polysaccharides containing amino acids
  • Cartilage is resistant to tension and compression but not as strong as bone however more flexible than bone
  • Keeps larger tubes open
• What happens in inspiration?

  • The external intercostal and diaphragm muscle contracts
  • This causes the ribcage to move upwards and outwards and the diaphragm to flatten- increasing the volume of the thorax
  • As volume of thorax increases the lung pressure decreases (below atmospheric pressure)
  • Causes air to flow to lungs
  • Active process
• What happens in expiration?

  • The external intercostal and diaphragm muscles relax
  • The ribcage moves downwards and inwards and the diaphragm becomes curved again
  • The thorax volume decreases causing the air pressure to increase ( above atmospheric pressure)
  • Air is forced out of the lungs
  • Can be a passive process
• What are the steps on how to use a spirometer?

  Its an oxygen filled chamber with a movable lid

  • Person breathes through a tube connected to the oxygen chamber
  • As the person breathes in and out the chamber moves up and down
  • These movements are recorded by a pen attached to the lid of the chamber-this writes on a rotating drum creating a spirometer trace
  • The soda lime in the tube the subject breathes into absorbs CO2
• What is the definition of tidal volume?

  The volume of air breathed in or out in an average breath during rest measured from the height of each peak at rest
• What is the definition of vital capacity?

  This is the maximum volume of air that can be inhaled or exhaled in one deep breath measured from the maximum peak height
• Why does the trace slow down on spirometer?

  • The air breathed into the spirometer has CO2 removed from it.
  • This is because of the soda lime