pulm phys exam one end of textbook questions

1. PP4: The ratio of total systemic vascular resistance to pulmonary vascular resistance is about: A. 2:1 B. 3:1 C. 5:1 D. 10:1 E. 20:1

D. 10:1

9. If the pressures in the capillaries and interstitial space at the top of the lung are 3 and 0 mm Hg, respectively, and the colloid osmotic pressures of the blood and interstitial fluid are 25 and 5 mm Hg, respectively, what is the net pressure in mm Hg moving fluid into the capillaries? A. 17 B. 20 C. 23 D. 27 E. 33

A. 17

11. A 45-year-old man is admitted with severe right lower lobe pneumonia and is placed on mechanical ventilation. On the 2nd hospital day, his hypoxemia worsens and a repeat chest radiograph shows increased opacities in both lungs. A blood gas reveals a pH of 7.47 and an arterial PO2 of 55 mm Hg while an echocardiogram demonstrates normal left ventricular function and left atrial size but significantly increased systolic pulmonary artery pressure. Which of the following factors likely accounts for the findings on his echocardiogram? A. Decreased alveolar PO2 B. Decreased arterial PO2 C. Decreased sympathetic nervous system activity D. Increased blood pH E. Increased pulmonary venous pressure

A. Decreased alveolar PO2

8. A 58-year-old woman with a long-standing use of ibuprofen for osteoar- thritis presents to her doctor because of excessive tiredness. Laboratory studies reveal a hemoglobin concentration of 9 g·dl−1 (normal 13 to 15 g·dl−1). Which of the following abnormalities would you most likely observe? A. Decreased diffusing capacity for carbon monoxide B. Decreased functional residual capacity C. Decreased residual volume D. Increased physiologic dead space E. Increased ventilation to the upper lung zones

A. Decreased diffusing capacity for carbon monoxide

6. A 65-year-old man complained of worsening dyspnea on exertion over a 6-month period. A lung biopsy was done because of changes seen on chest imaging. The pathology report states that the thickness of the thin side of the blood-gas barrier is greater than 0.8 μm in most of the alveoli. Which of the following would you expect? A. Decreased rate of diffusion of oxygen into the pulmonary capillaries B. Increase in volume of individual red cells C. Increased risk of rupture of the blood-gas barrier D. Slower diffusion of gas from the distal airways to the alveoli E. Decreased alveolar surfactant concentrations

A. Decreased rate of diffusion of oxygen into the pulmonary capillaries

1. PP1: The inspiratory flow-volume curve is most valuable for: A. Detecting fixed upper airway obstruction. B. Measuring the response to bronchodilator drugs. C. Differentiating between chronic bronchitis and emphysema. D. Detecting resistance in small peripheral airways. E. Detecting fatigue of the diaphragm.

A. Detecting fixed upper airway obstruction.

5. If CO2 production remains constant and alveolar ventilation is increased threefold, the alveolar Pco2 after a steady state is reached will be what percentage of its former value? A. 25 B. 33 C. 50 D. 100 E. 300

B. 33

3. What is the Po2 (in mm Hg) of moist inspired gas of a climber on the summit of Mt. Everest (assume barometric pressure is 247 mm Hg)? A. 32 B. 42 C. 52 D. 62 E. 72

B. 42

4 . A 72-year-old woman who is a heavy smoker complains of worsening dyspnea and a productive cough over a 9-month period. Spirometry shows an FEV1 1.1 liters, an FVC 2.8 liters, and an FEV1/FVC ratio of 0.39. Which of the following mechanisms best accounts for the results of these tests? A. Decreased lung compliance B. Dynamic compression of the airways C. Increased radial traction on the airways D. Increased thickness of the blood-gas barrier E. Weakness of the diaphragm

B. Dynamic compression of the airways

1. PP2: The only variable in the following list that cannot be measured with a simple spirometer and stopwatch is: A. Tidal volume B. Functional residual capacity C. Vital capacity D. Total ventilation E. Respiratory frequency

B. Functional residual capacity

8. Hypoxic pulmonary vasoconstriction: A. Depends more on the Po2 of mixed venous blood than alveolar gas B. Is released in the transition from placental to air respiration C. Involves CO2 uptake in vascular smooth muscle D. Partly diverts blood flow from well-ventilated regions of diseased lungs E. Is increased by inhaling low concentrations of nitric oxide

B. Is released in the transition from placental to air respiration

2. When oxygen moves through the thin side of the blood-gas barrier from the alveolar gas to the hemoglobin of the red blood cell, it traverses the following layers in order: A. Epithelial cell, surfactant, interstitium, endothelial cell, plasma, red cell membrane B. Surfactant, epithelial cell, interstitium, endothelial cell, plasma, red cell membrane C. Surfactant, endothelial cell, interstitium, epithelial cell, plasma, red cell membrane D. Epithelium cell, interstitium, endothelial cell, plasma, red cell membrane E. Surfactant, epithelial cell, interstitium, endothelial cell, red cell membrane

B. Surfactant, epithelial cell, interstitium, endothelial cell, plasma, red

2 . Concerning the single-breath nitrogen test: A. It is usually normal in mild COPD. B. The slope of phase 3 is increased in chronic bronchitis. C. In phase 3, well-ventilated units empty last. D. In normal subjects, the last expired gas comes from the base of the lung. E. The expiratory flow rate should be as fast as possible.

B. The slope of phase 3 is increased in chronic bronchitis.

2. Concerning the extra-alveolar vessels of the lung: A. Tension in the surrounding alveolar walls tends to narrow them. B. Their walls contain smooth muscle and elastic tissue. C. They are exposed to alveolar pressure. D. Their constriction in response to alveolar hypoxia mainly takes place in the veins. E. Their caliber is reduced by lung inflation.

B. Their walls contain smooth muscle and elastic tissue.

1. PR3: Using Fick's law of diffusion of gases through a tissue slice, if gas X is 4 times as soluble and 4 times as dense as gas Y, what is the ratio of the diffusion rates of X to Y? A. 0.25 B. 0.5 C. 2 D. 4 E. 8

C. 2

3. In a measurement of FRC by helium dilution, the original and final helium concentrations were 10% and 6%, and the spirometer volume was kept at 5 liters. What was the volume of the FRC in liters? A. 2.5 B. 3.0 C. 3.3 D. 3.8 E. 5.0

C. 3.3

5. In a measurement of cardiac output using the Fick principle, the O2 concentrations of mixed venous and arterial blood are 16 and 20 ml·100 ml−1, respectively, and the O2 consumption is 300 ml·min−1. The cardiac output in liters·min−1 is: A. 2.5 B. 5 C. 7.5 D. 10 E. 75

C. 7.5

2. An exercising subject breathes a low concentration of CO in a steady state. If the alveolar Pco is 0.5 mm Hg and the CO uptake is 30 ml·min−1, what is the diffusing capacity of the lung for CO in ml·min−1·mm·Hg−1? A. 20 B. 30 C. 40 D. 50 E. 60

E. 60

5. Concerning the diffusing capacity of the lung: A. It is best measured with carbon monoxide because this gas diffuses very slowly across the blood-gas barrier. B. Diffusion limitation of oxygen transfer during exercise is more likely to occur at sea level than at high altitude. C. Breathing oxygen reduces the measured diffusing capacity for carbon monoxide compared with air breathing. D. It is decreased by exercise. E. It is increased in pulmonary fibrosis, which thickens the blood-gas barrier.

C. Breathing oxygen reduces the measured diffusing capacity for carbon monoxide compared with air breathing.

4. If a subject inhales several breaths of a gas mixture containing low concentrations of carbon monoxide and nitrous oxide: A. The partial pressures of carbon monoxide in alveolar gas and end- capillary blood will be virtually the same. B. The partial pressures of nitrous oxide in alveolar gas and end-capillary blood will be very different. C. Carbon monoxide is transferred into the blood along the whole length of the capillary. D. Little of the nitrous oxide will be taken up in the early part of the capillary. E. The uptake of nitrous oxide can be used to measure the diffusing capacity of the lung.

C. Carbon monoxide is transferred into the blood along the whole length of the capillary.

7. A 63-year-old man with pulmonary fibrosis of unknown cause is referred for a cardiopulmonary exercise test in preparation for lung transplantation. He earlier underwent a lung biopsy, which revealed that the thin part of the blood-gas barrier in the involved areas was 0.9 μm in thickness. The diffusing capacity for carbon monoxide was only 40% of the predicted value. Compared to a normal individual, which of the following findings would you expect to see on the exercise test in this patient? A. Decreased inspired PO2 B. Decreased alveolar PO2 C. Decreased arterial PO2 D. Decreased anatomic dead space volume E. Increased rate of diffusion across the blood-gas barrier

C. Decreased arterial PO2

7. A 40-year-old man is receiving mechanical ventilation in the ICU after an admission for severe respiratory failure. The ventilator settings include a tidal volume of 600 ml and respiratory rate of 15. The patient is in a deep coma and cannot increase his total ventilation beyond what the ventilator is set to deliver. On his fifth hospital day, he develops high fevers and is determined to have a new blood stream infection. Which of the following changes would be expected as a result of this change in the patient's condition? A. Decrease in the physiologic dead space B. Decrease in the anatomic dead space C. Increase in the arterial PCO2 D. Increase in ventilation to the dependent regions of the lung E. Increase in the volume of gas delivered to the alveoli with each breath

C. Increase in the arterial PCO2

3 . The closing volume as measured from the single-breath N 2 test: A. Decreases with age. B. Is highly reproducible. C. Is affected by the small, peripheral airways. D. Is most informative in patients with severe lung disease. E. Is normal in mild COPD.

C. Is affected by the small, peripheral airways.

7. Pulmonary vascular resistance is reduced by: A. Removal of one lung B. Breathing a 10% oxygen mixture C. Exhaling from functional residual capacity to residual volume D. Acutely increasing pulmonary venous pressure E. Mechanically ventilating the lung with positive pressure

D. Acutely increasing pulmonary venous pressure

6. In zone 2 of the lung: A. Alveolar pressure exceeds arterial pressure. B. Venous pressure exceeds alveolar pressure. C. Venous pressure exceeds arterial pressure. D. Blood flow is determined by arterial pressure minus alveolar pressure. E. Blood flow is unaffected by arterial pressure.

D. Blood flow is determined by arterial pressure minus alveolar pressure.

4. The fall in pulmonary vascular resistance on exercise is caused by: A. Decrease in pulmonary arterial pressure B. Decrease in pulmonary venous pressure C. Increase in alveolar pressure D. Distension of pulmonary capillaries E. Alveolar hypoxia

D. Distension of pulmonary capillaries

2. Concerning the pulmonary acinus: A. Less than 90% oxygen uptake of the lung occurs in the acini. B. Percentage change in volume of the acini during inspiration is less than that of the whole lung. C. Volume of the acini is less than 90% of the total volume of the lung at FRC. D. Each acinus is supplied by a terminal bronchiole. E. The ventilation of the acini at the base of the upright human lung at FRC is less than that at the apex.

D. Each acinus is supplied by a terminal bronchiole.

6. The diffusing capacity of the lung for carbon monoxide is increased by: A. Emphysema, which causes loss of pulmonary capillaries. B. Asbestosis, which causes thickening of the blood-gas barrier. C. Pulmonary embolism, which cuts off the blood supply to part of the lung. D. Exercise in a normal subject. E. Severe anemia.

D. Exercise in a normal subject.

1. PP1: Concerning the blood-gas barrier of the human lung: A. The thinnest part of the blood-gas barrier has a thickness of about 3 μm. B. The total area of the blood-gas barrier is about 1 square meter. C. About 10% of the area of the alveolar wall is occupied by capillaries. D. If the pressure in the capillaries rises to abnormally high levels, the blood-gas barrier can be damaged. E. Oxygen crosses the blood-gas barrier by active transport.

D. If the pressure in the capillaries rises to abnormally high levels, the blood-gas barrier can be damaged.

6. A 56-year-old woman is started on mechanical ventilation after present- ing to the emergency department with acute respiratory failure. The ventilator is set to deliver a tidal volume of 750 mL 10 times per minute. After transfer to the ICU, the physician decreases her tidal volume to 500 mL and raises her respiratory rate to 15 breaths per minute. She is heavily sedated and does not initiate any breaths beyond what the ventilator gives to her (in other words, total ventilation is fixed). Which of the following changes would you expect to occur as a result of the physician's intervention? A. Decrease in the volume of the anatomic dead space B. Decrease in airway resistance C. Decrease inPaCO2 D. Increase in the dead space fraction E. Increase in CO2 production

D. Increase in the dead space fraction

7. A 57-year-old man undergoes spirometry because of chronic dyspnea on exertion. The flow-volume loop is depicted in the figure below. The blue dots show the predicted values. Which of the following factors could account for the shape of the flow-volume curve? (shows obstructive, scooped pattern) A. Fibrosis of the lung parenchyma B. Increased radial traction on the airways C. Increased elastic recoil D. Increased airway secretions E. Increased number of pulmonary capillaries

D. Increased airway secretions

Following admission to the intensive care unit after a severe myocardial infarction, a 62-year-old woman has increasing difficulty breathing. Laboratory studies reveal a serum albumin of 4.1 mg/dL (normal >4.0 mg/dL) and an arterial PO2 of 55 mm Hg. while a chest radiograph demonstrates a large heart and diffuse bilateral opacities, consistent with pulmonary edema. An echocardiogram is performed and demonstrates a dilated left ventricle with decreased systolic function, an enlarged left atrium, and mildly increased systolic pulmonary artery pressure. Which of the following factors most likely accounts for the development of pulmonary edema in this patient? A. Decreased arterial PO2 B. Decreased colloid osmotic pressure C. Increased lymphatic drainage from the pulmonary interstitium D. Increased pulmonary capillary hydrostatic pressure E. Recruitment and distention of the pulmonary vasculature

D. Increased pulmonary capillary hydrostatic pressure

5. Concerning the blood vessels of the human lung: A. The pulmonary veins form a branching pattern that matches that of the airways. B. The average diameter of the capillaries is about 50 μm. C. The bronchial circulation has about the same blood flow as does the pulmonary circulation. D. On the average, blood spends about 0.75 s in the capillaries under resting conditions. E. The mean pressure in the pulmonary artery is about 100 mm Hg.

D. On the average, blood spends about 0.75 s in the capillaries under resting conditions.

5 . A 61-year-old man with a 30-pack-year history of smoking complains of worsening dyspnea and a dry cough over a 6-month period. Spirometry shows an FEV1 of 1.9 liters, an FVC of 2.2 liters, and an FEV1/FVC ratio of 0.86. W hich of the following diseases is consistent with this presentation? A. Asthma B. Chronic bronchitis C. Chronic obstructive pulmonary disease D. Pulmonary fibrosis E. Pulmonary hypertension

D. Pulmonary fibrosis

10. The metabolic functions of the lung include: A. Converting angiotensin II to angiotensin I B. Producing bradykinin C. Secreting serotonin D. Removing leukotrienes E. Generating erythropoietin

D. Removing leukotrienes

4. A patient sits in a body plethysmograph (body box) and makes an expira- tory effort against his closed glottis. What happens to the following: pressure in the lung airways, lung volume, box pressure, box volume? A. airway P: decreases, lung vol: increases, box pressure: increases, box volume: decreases B. airway P: decreases, lung vol: increases, box pressure: decreases, box volume: increases C. airway P: increases, lung vol: decreases, box pressure: increases, box volume: decreases D. airway P: increases, lung vol: decreases, box pressure: decreases, box volume: increases E. airway P: increases, lung vol: increases, box pressure: decreases, box volume: decreases

D. airway P: increases, lung vol: decreases, box pressure: decreases, box volume: increases

3. A patient with pulmonary vascular disease has mean pulmonary arterial and venous pressures of 55 and 5 mm Hg, respectively, while the cardiac output is 3 liters·min−1. What is his pulmonary vascular resistance in mm Hg·liters−1·min? A. 0.5 B. 1.7 C. 2.5 D. 5 E. 17

E. 17

4. Concerning the airways of the human lung: A. The volume of the conducting zone is about 50 ml. B. The volume of the rest of the lung during resting conditions is about 5 liters. C.A respiratory bronchiole can be distinguished from a terminal bronchiole because the latter has alveoli in its walls. D. On the average, there are about three branchings of the conducting airways before the first alveoli appear in their walls. E. In the alveolar ducts, the predominant mode of gas flow is diffusion rather than convection.

E. In the alveolar ducts, the predominant mode of gas flow is diffusion rather than convection.

3. In a normal person, doubling the diffusing capacity of the lung would be expected to: A. Decrease arterial Pco2 during resting breathing. B. Increase resting oxygen uptake when the subject breathes 10% oxygen. C. Increase the uptake of nitrous oxide during anesthesia. D. Increase the arterial Po2 during resting breathing. E. Increase maximal oxygen uptake at extreme altitude.

E. Increase maximal oxygen uptake at extreme altitude.

6 . A 41-year-old woman performs spirometry because she complains of dyspnea. She did not give a full effort on the first test and was asked by the laboratory technologist to repeat the test a second time. Which of the following changes in her spirometry would you expect to see if she makes a better effort on the second trial? A. Decreased vital capacity B. Flattening of the expiratory limb of the flow-volume loop C. Flattening on the inspiratory limb of the flow-volume loop D. Increased expiratory flow at end exhalation E. Increased peak expiratory flow rate

E. Increased peak expiratory flow rate