Anatomical Dead Space

• • The bronchiole tree bifurcates into branches down to the trachea, then main bronchi then right and left lungs
  • goes for 16 generations - called conducting zone, where gas exchange doesnt occur, air moves via convection
  • conducting zone is known as anatomical dead space as it holds air as it comes in, but no gas exchange takes place
  • air is directed to the respiratory zone where gas exchange can occur
• Anatomical dead space:

  • located in the conducting zone (first 16 generations of the bronchiole tree)
  • no gas exchange occurs, air moves via convection to respiratory zone
  • ~ 150 mls

  
• After first 16 generations (after anatomical dead space):

  • we enter the respiratory zone
  • airways that lead to alveolar membrane / gas exchange surface
  • 7 generations in the respiratory zone
  • air moves via diffusion
• Anatomical dead space:

  • With each tidal volume, 150 mls remains in conducting zone up to terminal bronchioles
  • This is called Anatomical dead space
  • therefore only 350 mls reach the gas exchange surface
  • all 500 mls gets expired
• Intubated patient:

  • external tubes increase anatomical dead space