Respiratory System

Topics in this chapter

• Respiratory Mechanics and Muscles
• Lung Volumes and Function Tests
• Ventilation-Perfusion Relationships
• Alveolar Gas Exchange
• Oxygen Transport and Hemoglobin
• Carbon Dioxide Transport and Acid-Base Balance
• Control of Breathing

Practice questions

1. Question 1Q-BABD46

   A 28-year-old male undergoes pulmonary function testing. His forced expiratory volume in one second (FEV1) is 80% of predicted, forced vital capacity (FVC) is 82% of predicted, and the FEV1/FVC ratio is 0.82. Total lung capacity (TLC) is measured at 55% of predicted. These findings are most consistent with which of the following conditions?

   1. A.Chronic obstructive pulmonary disease (COPD)
   2. B.Idiopathic pulmonary fibrosis
   3. C.Asthma with air trapping
   4. D.Normal pulmonary function
   See the answer and solution
2. Question 2Q-4609F8

   During a maximal expiration, a subject reaches residual volume. At this point, the inward elastic recoil of the lungs and the outward elastic recoil of the chest wall are related in which of the following ways?

   1. A.Lung recoil is zero; chest wall recoil is outward and maximal.
   2. B.Inward lung recoil equals outward chest wall recoil.
   3. C.Outward chest wall recoil is greater than inward lung recoil.
   4. D.Inward lung recoil is greater than outward chest wall recoil.
   See the answer and solution
3. Question 3Q-A569AA

   A healthy medical student is breathing air at sea level. If her arterial blood gas analysis shows PaO2 = 100 mmHg, PaCO2 = 40 mmHg, and her respiratory exchange ratio (R) is 0.8, what is her approximate alveolar oxygen tension (PAO2) using the alveolar gas equation?

   1. A.95 mmHg
   2. B.100 mmHg
   3. C.105 mmHg
   4. D.115 mmHg
   See the answer and solution
4. Question 4Q-80F739

   Which of the following regional differences characterizes a normal upright lung at the level of the functional residual capacity (FRC)?

   1. A.Alveoli at the apex are smaller than those at the base.
   2. B.Blood flow is highest at the apex and lowest at the base.
   3. C.Ventilation-perfusion ratio is highest at the apex.
   4. D.Pleural pressure is more negative at the base than at the apex.
   See the answer and solution
5. Question 5Q-7DBD49

   A patient with severe metabolic acidosis develops compensatory hyperventilation (Kussmaul breathing). Which of the following changes is primarily responsible for mediating this respiratory response?

   1. A.Direct stimulation of medullary respiratory centers by low arterial pH
   2. B.Stimulation of peripheral chemoreceptors by decreased arterial PO2
   3. C.Stimulation of central chemoreceptors due to a decrease in cerebrospinal fluid pH
   4. D.Activation of pulmonary J-receptors by increased pulmonary capillary pressure
   See the answer and solution