flashcards

• What are the walls of alveoli made of

  A single layer of thin flat epithelium cells called the alveolar epithelium
• What are the walls of capillaries made of


  Capillary endothelium that is one cell thick

  One cell thick - provides short diffusion pathway
• What do the walls of alveoli contain and function

  Contains elastic fibres

  Helps alveoli recoil to their normal shape after inhaling or exhaling air
• Describe how oxygen from the air moves through the gas exchange system into the blood 


  Air containing oxygen moves down trachea, bronchi, bronchioles and into the alveoli down a presssure gradient.

  Oxygen then diffuses out of alveoli into haemoglobin in the blood across alveolar epithelium and capillary endothelium down a diffusion gradient
• What type of cells is capillary endothelium made of

  Endothelial cells
• Describe how oxygen moves from the alveoli into blood 


  Diffuses out of alveoli across alveolar epithelium and capillary endothelium and into haemoglobin in the blood down diffusion gradient
• What two layers do gases have to diffuse over in gas exchange

  Alveolar epithelium

  Capillary endothelium
• Describe how carbon dioxide moves out of blood and back into the air


  Diffuses out of blood into alveoli across capillary endothelium and alveolar epithelial down a concentration gradient

  Then moves through bronchioles, bronchi, trachea and into the air
• Summary of the path oxygen takes through the gas exchange system from air to blood 


  Trache, bronchi, bronchioles, alveoli, alveolar epithelium, capillary endothelium and blood
• How are alveoli/lungs adapted to speed up rate diffusing

  • Alveolar epithelium is only one cell thick providing thin exchange surface and shirt diffusion pathway
  • Millions of alveoli provides lungs large aurfae area for gas exchange
  • Lots of capillaries - maintains a steep concentration gradient
  • Ventilation removes co2 and bright new 02 into lungs, maintaining a steep concentration gradient
• Why do alveoli have a thin exchange surface

  Alveolar epithelium is one cell thick
• How does the flow of blood increase the rate of diffuse in gas exchange 


  Maintains steep concentration gradient by rapidly replacing blood high in 02 and blood low in 02