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  1. What is the primary function of the respiratory system?
    Gas exchange
  2. What is the secondary (second most important) function of the respiratory system?
    Acid-base balance via CO2 removal
  3. What are the 5 major functions of the respiratory system?
    • 1) gas exchange
    • 2) acid-base balance
    • 3) phonation
    • 4) pulmonary defense mechanisms
    • 5) pulmonary metabolism and handling of bioactive materials
  4. Approximately how many alveoli are there in the human lungs?
    300 million
  5. About how many pulmonary capillaries are there in each alveolus?
    • Nearly 1000 capillaries per alveolus
    • Each alveolus is almost completely enveloped in pulmonary capillaries
  6. What is the approximate surface area available for gas exchange?
    • 50-100 square meters
    • Average is 80 square meters
    • About the size of 900 square feet
  7. By what mechanism does gas exchange take place?
  8. What is the role of surfactant in alveoli?
    Maintain distensibility
  9. What, besides diffusion, promotes CO2 movement out of the RBC?
    Hamburger shift
  10. Where does gas exchange occur?
    Alveolar-capillary unit
  11. What is the partial pressure of oxygen in dry air?
    21% * 760mmHg = 159mmHg
  12. What is the vapor pressure of water at normal body temperature (37 degrees C)?
  13. What is the total pressure of air after being warmed and moistened in the trachea?
    760 - 47 = 713mmHg
  14. What is the partial pressure of oxygen in the trachea?
    • 21% * 713 = 149mmHg
    • MUST subtract the partial pressure exerted by water vapor from atmospheric pressure BEFORE calculating the partial pressure of inspired oxygen
  15. Describe type I alveolar cells
    • AKA pneumocytes
    • Flat and form tight junctions with one another
    • Prevent passage of large, oncotic molecules into alveolus
  16. Describe type II alveolar cells
    • Interspersed among type I cells
    • Produce pulmonary surfactant that lines alveoli
  17. Describe alveolar macrophage
    Phagocytic cells that destroy inspired particles like bacteria
  18. Describe the progression of conducting airways
    • 1) Trachea
    • 2) right and left main bronchi
    • 3) lobar bronchi
    • 4) segmental bronchi
    • 5) Terminal Bronchioles
  19. How many generations of airways are there?
  20. What generation is the trachea?
    0th generation
  21. What is the first generation of airway?
    Right and left mainstem bronchi
  22. What is the difference between the right and left main bronchi?
    Right is more parallel to trachea and larger diameter than left
  23. How many generations compose the conducting zones?
    16 generations
  24. What are the most distal conducting airways?
    Terminal bronchioles
  25. What generation are terminal bronchioles?
    16th generation
  26. What portion of the conducting zone is deadspace? What is the volume?
    • All of it
    • 150ml
  27. What is another term for deadspace created by the conducting zone?
    Anatomic deadspace
  28. What structures are included in anatomic deadspace?
    Airways from nose and lips down to alveoli-free terminal bronchioles
  29. What is the function of the conducting zone?
    Move air to the area where gas exchange occurs
  30. By what mechanism does the conducting zone move air?
    Convective flow
  31. What airway generations make up the transitional zone?
  32. What structures are included in the transitional zone?
    • Appearance of alveoli
    • Respiratory bronchioles
  33. What airway generations make up the respiratory zone?
  34. What structures are included in the respiratory zone?
    • Alveolar ducts lined with alveoli
    • Alveolar sacs
  35. What is the volume of the respiratory zone?
    2.5-3 liters
  36. What is the mechanism of gas movement in the respiratory zone?
  37. What blood supplies do the lungs receive?
    • 1) pulmonary arteries
    • 2) bronchial arteries
  38. Besides pulmonary arteries, what other arteries carries deoxygenated blood?
    Umbilical arteries in fetus
  39. What portion of cardiac output do pulmonary arteries receive?
    • All of it
    • 6 liters/min
  40. What is the mean pulmonary artery pressure?
  41. What is the average diameter of capillaries that supply alveoli?
    • 7-10 micrometers
    • Just large enough for RBC to pass single-file
  42. How do pulmonary capillaries form a continuous sheet of blood in alveolar wall?
    The lengths of capillary segments are short
  43. What is the thickness of the blood-gas barrier?
    0.2-0.3 micrometer
  44. How long does a RBC normally spend in the pulmonary capillary network?
    0.75 second
  45. How many alveoli does a RBC normally traverse in pulmonary capillary network?
    2-3 alveoli
  46. What structures do bronchial arteries supply?
    Conducting airways
  47. What happens to bronchial arteries at the level of respiratory bronchioles?
    • Anastomose with pulmonary artery capillaries
    • Blood from bronchial circulation partially drains into pulmonary veins creating a small PHYSIOLOGICAL shunt (right to left)
Card Set
West Ch 1
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