Lung Mechanics

9 Questions | Total Attempts: 959

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Lung Mechanics

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Questions and Answers
  • 1. 
    The compliance of the respiratory system IS changing with lung volume. At which lung volume has the respiratory systsm It 's greates compliance?
    • A. 

      FRC

    • B. 

      RV

    • C. 

      TLC

    • D. 

      Minimal lung volume (below RV)

  • 2. 
    A patient inhales 2 L of air and holds his breath. At the beginning of inspiration his lung transmural pressure is + 5 cm H20. During breath holding his lung transmural pressure is + 10 cm H20 . What is his lung compliance in L / cm H20 ?
    • A. 

      0.1

    • B. 

      0.2

    • C. 

      0.3

    • D. 

      0.4

    • E. 

      0.5

  • 3. 
    Breathing is associated with changes in intra pleural pressure (PPI)' During which of the following respirations can this pressure become positive (greater than atmospheric pressure) .
    • A. 

      During normal inspiration

    • B. 

      During normal expiration

    • C. 

      During forced inspiration of a large volume (3 L)

    • D. 

      During forced expiration of a large volume (3 L)

    • E. 

      During breath holding at FRC

  • 4. 
    A Patient is suffering form obstructive lung disease. His chest wall and respiratory system compliances are measured as: Chest wall compliance (Ccw)= 200 ml / cm H20 Respiratory system compliance (Crs)= 100 ml/ cm H20 What is Lung Compliance (Cl) in ml / cm H20
    • A. 

      50

    • B. 

      100

    • C. 

      200

    • D. 

      300

    • E. 

      400

  • 5. 
    A patient has a skeletal abnorrnalltv (Kyphoscohosis). You are interested to verify the compliance of his chest wall. You are measuring changes in lung volume by a spirometer. Which pressure change you have to measure in addition to DV to be able to determine the compliance of his chest wall?
    • A. 

      Changes In alveolar pressure (D,PA)

    • B. 

      Changes in intra pleural pressure (D,Ppl)

    • C. 

      Changes In airway pressure (D,Paw)

    • D. 

      Changes in alveolar 02-partial pressure (D,PAO2)

    • E. 

      Changes in inspired O2-partial pressure (D,PIO2)

  • 6. 
    You are called to examine a premature early born infant. He is suffering from breathlessness and is cyanotic. Your diagnosis is "infant respiratory distress svridrome, (IRDS). After treatment with artifrciaI surfactant, the situation is under control. What did surfactant do?
    • A. 

      It decreased the lung compliance

    • B. 

      It decreased surface tension in the lung

    • C. 

      It increased the force of respiratory muscles

    • D. 

      It Increased the activity of inspiratory motor neurons

    • E. 

      It increased the concentration of erythrocytes in the blood

  • 7. 
    A premature baby with difficulty breathing probably has :
    • A. 

      An increased FRC

    • B. 

      An increased TLC

    • C. 

      A decreased RV.

    • D. 

      A and C.

  • 8. 
    Contraction of the abdominal muscles is important in
    • A. 

      Normal (quiet) inspiration.

    • B. 

      Forced (maximum) inspiration

    • C. 

      Normal (quiet) expiration

    • D. 

      Forced (maximum) expiration.

    • E. 

      None of the above

  • 9. 
    Alveolar surfactant acts to INCREASE pulmonary
    • A. 

      Surface tension

    • B. 

      Compliance

    • C. 

      Airway resistance