Physiology BRS Test 3 Questions

Of the following, the MOST appropriate statement about the relationship between lung volume and pressure is that: a. The lung is most compliant at peak inflation b. The pressure volume curve is identical during inflation and deflation c. A saline filled lung is more compliant than an air filled lung d. There is a linear relationship between volume and pressure

. A saline filled lung is more compliant than an air filled lung d. There is a linear relationship

2. An infant born prematurely in gestational week 25 has neonatal respiratory distress syndrome. Which of the following would be expected in this infant? A. Arterial Po2 of 100 mm Hg B. Collapse of the small alveoli C. Increased lung compliance D. Normal breathing rate E. Lecithin:sphingomyelin ratio of greater than 2:1 in amniotic fluid

2. The answer is B [II D 2]. Neonatal respiratory distress syndrome is caused by lack of adequate surfactant in the immature lung. Surfactant appears between the 24th and the 35th gestational week. In the absence of surfactant, the surface tension of the small alveoli is too high. When the pressure on the small alveoli is too high (P = 2T/r), the small alveoli collapse into larger alveoli. There is decreased gas exchange with the larger, collapsed alveoli; and ventilation/perfusion (V/Q) mismatch, hypoxemia, and cyanosis occur. The lack of surfactant also decreases lung compliance, making it harder to inflate the lungs, increasing the work of breathing, and producing dyspnea (shortness of breath). Generally, lecithin:sphingomyelin ratios greater than 2:1 signify mature levels of surfactant.

3. In which vascular bed does hypoxia cause vasoconstriction? A. Coronary B. Pulmonary C. Cerebral D. Muscle E. Skin

3. The answer is B [VI C]. Pulmonary blood flow is controlled locally by the Po2 of alveolar air. Hypoxia causes pulmonary vasoconstriction and thereby shunts blood away from unventilated areas of the lung, where it would be wasted. In the coronary circulation, hypoxemia causes vasodilation. The cerebral, muscle, and skin circulations are not controlled directly by Po2.

Which of the following sets of data would have the highest rate of O2 transfer in the lungs?

30. The answer is C [III D]. The diffusion of O2 from alveolar gas to pulmonary capillary blood is proportional to the partial pressure difference for O2 between inspired air and mixed venous blood entering the pulmonary capillaries, proportional to the surface area for diffusion and inversely proportional to diffusion distance or thickness of the barrier.

14. The shift from curve A to curve B is associated with A. increased P50 B. increased affinity of hemoglobin for O2 C. impaired ability to unload O2 in the tissues D. increased O2-carrying capacity of hemoglobin E. decreased O2-carrying capacity of hemoglobin

The answer is A [IV C 1; Figure 4.8]. A shift to the right of the hemoglobin-O2 dissociation curve represents decreased affinity of hemoglobin for O2. At any given Po2, the percent saturation is decreased, the P50 is increased (read the Po2 from the graph at 50% hemoglobin saturation), and unloading of O2 in the tissues is facilitated. The O2-carrying capacity of hemoglobin is the mL of O2 that can be bound to a gram of hemoglobin at 100% saturation and is unaffected by the shift from curve A to curve B.

15. Which volume remains in the lungs after a maximal expiration? A. Tidal volume (Vt) B. Vital capacity (VC) C. Expiratory reserve volume (ERV) D. Residual volume (RV) E. Functional residual capacity (FRC) F. Inspiratory capacity G. Total lung capacity

The answer is D [I A 3]. During a forced maximal expiration, the volume expired is a tidal volume (Vt) plus the expiratory reserve volume (ERV). The volume remaining in the lungs is the residual volume (RV).

A 62-year-old man at sea level breaths a gas mixture containing 21% O2. He has the following arterial blood gas values: PaO2 = 60 mm Hg PaCO2 = 70 mm Hg Which of the following is the cause of his hypoxemia? A. Hypoventilation B. Fibrosis C. V/Q defect D. Right-to-left shunt E. Anemia

The answer is A [IV D]. Anemia (or decreased hemoglobin concentration) is eliminated because it causes decreased O2 content of blood but does not cause hypoxemia. The remaining choices all cause hypoxemia. Calculating the A-a gradient distinguishes between these causes as follows: Pio2 = (760 mm Hg − 47 mm Hg) × 0.21 = 150 mm Hg. PaO2 = 150 mm Hg − 70 mm Hg/0.8 = 63 mm Hg. A-a gradient = 63 mm Hg − 60 mm Hg = 3 mm Hg, which is normal. Among the choices, the only cause of hypoxemia with a normal A-a gradient is hypoventilation, whereby PaO2 is lowered by hypoventilation and PaO2 equilibrates with that lowered value; since PaO2 and PaO2 are equilibrated (but lower than normal), they are essentially equal and A-a is close to zero, or normal. Fibrosis, V/Q defect, and right-to-left shunt all cause decreased PaO2 that is not equilibrated with PaO2 and thus cause increased A-a gradient.

Which person would be expected to have the largest A-a gradient? A. Person with pulmonary fibrosis B. Person who is hypoventilating due to morphine overdose C. Person at 12,000 feet above sea level D. Person with normal lungs breathing 50% O2 E. Person with normal lungs breathing 100% O2

The answer is A [IV D]. Increased A-a gradient signifies lack of O2 equilibration between alveolar gas (A) and systemic arterial blood (a). In pulmonary fibrosis, there is thickening of the alveolar/pulmonary capillary barrier and increased diffusion distance for O2, which results in lack of equilibration of O2, hypoxemia, and increased A-a gradient. Hypoventilation and ascent to 12,000 feet also cause hypoxemia, because systemic arterial blood is equilibrated with a lower alveolar Po2 (normal A-a gradient). Persons breathing 50% or 100% O2 will have elevated alveolar Po2, and their arterial Po2 will equilibrate with this higher value (normal A-a gradient).

Which of the following changes occurs during strenuous exercise? A. Ventilation rate and O2 consumption increase to the same extent B. Systemic arterial Po2 decreases to about 70 mm Hg C. Systemic arterial Pco2 increases to about 60 mm Hg D. Systemic venous Pco2 decreases to about 20 mm Hg E. Pulmonary blood flow decreases at the expense of systemic blood flow

The answer is A [IX A]. During exercise, the ventilation rate increases to match the increased O2 consumption and CO2 production. This matching is accomplished without a change in mean arterial Po2 or Pco2. Venous Pco2 increases because extra CO2 is being produced by the exercising muscle. Because this CO2 will be blown off by the hyperventilating lungs, it does not increase the arterial Pco2. Pulmonary blood flow (cardiac output) increases manifold during strenuous exercise.

In the transport of CO2 from the tissues to the lungs, which of the following occurs in venous blood? A. Conversion of CO2 and H2O to H+ and HCO3− in the red blood cells (RBCs) B. Buffering of H+ by oxyhemoglobin C. Shifting of HCO3− into the RBCs from plasma in exchange for Cl− D. Binding of HCO3− to hemoglobin E. Alkalinization of the RBCs

The answer is A [V B; Figure 4.9]. CO2 generated in the tissues is hydrated to form H+ and HCO3− in red blood cells (RBCs). H+ is buffered inside the RBCs by deoxyhemoglobin, which acidifies the RBCs. HCO3− leaves the RBCs in exchange for Cl− and is carried to the lungs in the plasma. A small amount of CO2 (not HCO3−) binds directly to hemoglobin (carbaminohemoglobin).

27. In a maximal expiration, the total volume expired is A. tidal volume (Vt) B. vital capacity (VC) C. expiratory reserve volume (ERV) D. residual volume (RV) E. functional residual capacity (FRC) F. inspiratory capacity G. total lung capacity

The answer is B [I B 3]. The volume expired in a forced maximal expiration is forced vital capacity, or vital capacity (VC).

17. A healthy 65-year-old man with a tidal volume (Vt) of 0.45 L has a breathing frequency of 16 breaths/min. His arterial Pco2 is 41 mm Hg, and the Pco2 of his expired air is 35 mm Hg. What is his alveolar ventilation? A. 0.066 L/min B. 0.38 L/min C. 5.0 L/min D. 6.14 L/min E. 8.25 L/min

The answer is D [I A 5 b, 6 b]. Alveolar ventilation is the difference between tidal volume (Vt) and dead space multiplied by breathing frequency. Vt and breathing frequency are given, but dead space must be calculated. Dead space is Vt multiplied by the difference between arterial Pco2 and expired Pco2 divided by arterial Pco2. Thus, dead space = 0.45 × (41 − 35/41) = 0.066 L. Alveolar ventilation is then calculated as (0.45 L − 0.066 L) × 16 breaths/min = 6.14 L/min.

Which of the following causes of hypoxia is characterized by a decreased arterial Po2 and an increased A-a gradient? A. Hypoventilation B. Right-to-left cardiac shunt C. Anemia D. Carbon monoxide poisoning E. Ascent to high altitude

The answer is B [IV A 4; IV D; Table 4.4; Table 4.5]. Hypoxia is defined as decreased O2 delivery to the tissues. It occurs as a result of decreased blood flow or decreased O2 content of the blood. Decreased O2 content of the blood is caused by decreased hemoglobin concentration (anemia), decreased O2-binding capacity of hemoglobin (carbon monoxide poisoning), or decreased arterial Po2 (hypoxemia). Hypoventilation, right-to-left cardiac shunt, and ascent to high altitude all cause hypoxia by decreasing arterial Po2. Of these, only right-to-left cardiac shunt is associated with an increased A-a gradient, reflecting a lack of O2 equilibration between alveolar gas and systemic arterial blood. In right-to-left shunt, a portion of the right heart output, or pulmonary blood flow, is not oxygenated in the lungs and thereby "dilutes" the Po2 of the normally oxygenated blood. With hypoventilation and ascent to high altitude, both alveolar and arterial Po2 are decreased, but the A-a gradient is normal.

16. Compared with the systemic circulation, the pulmonary circulation has a A. higher blood flow B. lower resistance C. higher arterial pressure D. higher capillary pressure E. higher cardiac output

The answer is B [VI A]. Blood flow (or cardiac output) in the systemic and pulmonary circulations is nearly equal; pulmonary flow is slightly less than systemic flow because about 2% of the systemic cardiac output bypasses the lungs. The pulmonary circulation is characterized by both lower pressure and lower resistance than the systemic circulation, so flows through the two circulations are approximately equal (flow = pressure/resistance).

If an area of the lung is not ventilated because of bronchial obstruction, the pulmonary capillary blood serving that area will have a Po2 that is A. equal to atmospheric Po2 B. equal to mixed venous Po2 C. equal to normal systemic arterial Po2 D. higher than inspired Po2 E. lower than mixed venous Po2

The answer is B [VII B 1]. If an area of lung is not ventilated, there can be no gas exchange in that region. The pulmonary capillary blood serving that region will not equilibrate with alveolar Po2 but will have a Po2 equal to that of mixed venous blood.

Compared with the apex of the lung, the base of the lung has A. a higher pulmonary capillary Po2 B. a higher pulmonary capillary Pco2 C. a higher ventilation/perfusion (V/Q) ratio D. the same V/Q ratio

The answer is B [VII C; Figure 4.10; Table 4.5]. Ventilation and perfusion of the lung are not distributed uniformly. Both are lowest at the apex and highest at the base. However, the differences for ventilation are not as great as for perfusion, making the ventilation/perfusion (V/Q) ratios higher at the apex and lower at the base. As a result, gas exchange is more efficient at the apex and less efficient at the base. Therefore, blood leaving the apex will have a higher Po2 and a lower Pco2.

A 12-year-old boy has a severe asthmatic attack with wheezing. He experiences rapid breathing and becomes cyanotic. His arterial Po2 is 60 mm Hg and his Pco2 is 30 mm Hg. 5. To treat this patient, the physician should administer A. an α1-adrenergic antagonist B. a β1-adrenergic antagonist C. a β2-adrenergic agonist D. a muscarinic agonist E. a nicotinic agonist

The answer is C [II E 3 a (2)]. A cause of airway obstruction in asthma is bronchiolar constriction. β2-adrenergic stimulation (β2-adrenergic agonists) produces relaxation of the bronchioles.

11. Which of the following is the site of highest airway resistance? A. Trachea B. Largest bronchi C. Medium-sized bronchi D. Smallest bronchi E. Alveoli

The answer is C [II E 4]. The medium-sized bronchi actually constitute the site of highest resistance along the bronchial tree. Although the small radii of the alveoli might predict that they would have the highest resistance, they do not because of their parallel arrangement. In fact, early changes in resistance in the small airways may be "silent" and go undetected because of their small overall contribution to resistance.

13. In the hemoglobin-O2 dissociation curves shown above, the shift from curve A to curve B could be caused by A. increased pH B. decreased 2,3-diphosphoglycerate (DPG) concentration C. strenuous exercise D. fetal hemoglobin (HbF) E. carbon monoxide (CO) poisoning

The answer is C [IV C 1; Figure 4.8]. Strenuous exercise increases the temperature and decreases the pH of skeletal muscle; both effects would cause the hemoglobin-O2 dissociation curve to shift to the right, making it easier to unload O2 in the tissues to meet the high demand of the exercising muscle. 2,3-Diphosphoglycerate (DPG) binds to the β chains of adult hemoglobin and reduces its affinity for O2, shifting the curve to the right. In fetal hemoglobin, the β chains are replaced by γ chains, which do not bind 2,3-DPG, so the curve is shifted to the left. Because carbon monoxide (CO) increases the affinity of the remaining binding sites for O2, the curve is shifted to the left.

9. When a person is standing, blood flow in the lungs is: A. equal at the apex and the base B. highest at the apex owing to the effects of gravity on arterial pressure C. highest at the base because that is where the difference between arterial and venous pressure is greatest D. lowest at the base because that is where alveolar pressure is greater than arterial pressure

The answer is C [VI B]. The distribution of blood flow in the lungs is affected by gravitational effects on arterial hydrostatic pressure. Thus, blood flow is highest at the base, where arterial hydrostatic pressure is greatest and the difference between arterial and venous pressure is also greatest. This pressure difference drives the blood flow.

10. Which of the following is illustrated in the graph showing volume versus pressure in the lung-chest wall system?

The answer is D [II C 2; Figure 4.3]. By convention, when airway pressure is equal to atmospheric pressure, it is designated as zero pressure. Under these equilibrium conditions, there is no airflow because there is no pressure gradient between the atmosphere and the alveoli, and the volume in the lungs is the functional residual capacity (FRC). The slope of each curve is compliance, not resistance; the steeper the slope is, the greater the volume change is for a given pressure change, or the greater compliance is. The compliance of the lungs alone or the chest wall alone is greater than that of the combined lung-chest wall system (the slopes of the individual curves are steeper than the slope of the combined curve, which means higher compliance). When airway pressure is zero (equilibrium conditions), intrapleural pressure is negative because of the opposing tendencies of the chest wall to spring out and the lungs to collapse.

A 48-year-old woman at sea level breaths a gas mixture containing 21% O2. She has the following arterial blood gas values: PaO2 = 60 mm Hg PaCO2 = 45 mm Hg Her measured DLCO is normal. Which of the following is the cause of her hypoxemia? A. The values demonstrate normal lung function B. Hypoventilation C. Fibrosis D. Carbon monoxide poisoning E. Right-to-left shunt

The answer is D [IV D]. Since the woman is hypoxemic at sea level and breathing a mixture containing a normal % of O2, she cannot have normal lung function. Also, because she is hypoxemic, she does not have carbon monoxide poisoning (which would decrease O2 content of blood but would not decrease PaO2). The remaining choices of hypoventilation, fibrosis, and right-to-left shunt cause hypoxemia. Fibrosis can be eliminated because it causes a diffusion defect and decreased DLCO. Hypoventilation can be eliminated because it would cause greatly increased PaCO2. Right-to-left shunt as the cause of the woman's hypoxemia is further supported by calculating the A-a gradient as follows. Pio2 = (760 mm Hg − 47 mm Hg) × 0.21 = 150 mm Hg. PaO2 = 150 mm Hg − 45 mm Hg/0.8 = 94 mm Hg. A-a gradient = 94 mm Hg − 60 mm Hg = 34 mm Hg, which is increased and consistent with right-to-left shunt.

A 38-year-old woman moves with her family from New York City (sea level) to Leadville, Colorado (10,200 feet above sea level). Which of the following will occur as a result of residing at high altitude? A. Hypoventilation B. Arterial Po2 greater than 100 mm Hg C. Decreased 2,3-diphosphoglycerate (DPG) concentration D. Shift to the right of the hemoglobin-O2 dissociation curve E. Pulmonary vasodilation F. Hypertrophy of the left ventricle G. Respiratory acidosis

The answer is D [IX B; Table 4.9]. At high altitudes, the Po2 of alveolar air is decreased because barometric pressure is decreased. As a result, arterial Po2 is decreased (<100 mm Hg), and hypoxemia occurs and causes hyperventilation by an effect on peripheral chemoreceptors. Hyperventilation leads to respiratory alkalosis. 2,3-Diphosphoglycerate (DPG) levels increase adaptively; 2,3-DPG binds to hemoglobin and causes the hemoglobin-O2 dissociation curve to shift to the right to improve unloading of O2 in the tissues. The pulmonary vasculature vasoconstricts in response to alveolar hypoxia, resulting in increased pulmonary arterial pressure and hypertrophy of the right ventricle (not the left ventricle).

26. The pH of venous blood is only slightly more acidic than the pH of arterial blood because A. CO2 is a weak base B. there is no carbonic anhydrase in venous blood C. the H+ generated from CO2 and H2O is buffered by HCO3- in venous blood D. the H+ generated from CO2 and H2O is buffered by deoxyhemoglobin in venous blood E. oxyhemoglobin is a better buffer for H+ than is deoxyhemoglobin

The answer is D [V B]. In venous blood, CO2 combines with H2O and produces the weak acid H2CO3, catalyzed by carbonic anhydrase. The resulting H+ is buffered by deoxyhemoglobin, which is such an effective buffer for H+ (meaning that the pK is within 1.0 unit of the pH of blood) that the pH of venous blood is only slightly more acid than the pH of arterial blood. Oxyhemoglobin is a less effective buffer than is deoxyhemoglobin.

A 49-year-old man has a pulmonary embolism that completely blocks blood flow to his left lung. As a result, which of the following will occur? A. Ventilation/perfusion (V/Q) ratio in the left lung will be zero B. Systemic arterial Po2 will be elevated C. V/Q ratio in the left lung will be lower than in the right lung D. Alveolar Po2 in the left lung will be approximately equal to the Po2 in inspired air E. Alveolar Po2 in the right lung will be approximately equal to the Po2 in venous blood

The answer is D [VII B 2]. Alveolar Po2 in the left lung will equal the Po2 in inspired air. Because there is no blood flow to the left lung, there can be no gas exchange between the alveolar air and the pulmonary capillary blood. Consequently, O2 is not added to the capillary blood. The ventilation/perfusion (V/Q) ratio in the left lung will be infinite (not zero or lower than that in the normal right lung) because Q (the denominator) is zero. Systemic arterial Po2 will, of course, be decreased because the left lung has no gas exchange. Alveolar Po2 in the right lung is unaffected.

A 12-year-old boy has a severe asthmatic attack with wheezing. He experiences rapid breathing and becomes cyanotic. His arterial Po2 is 60 mm Hg and his Pco2 is 30 mm Hg. 4. Which of the following statements about this patient is most likely to be true? A. Forced expiratory volume1/forced vital capacity (FEV1/FVC) is increased B. Ventilation/perfusion (V/Q) ratio is increased in the affected areas of his lungs C. His arterial Pco2 is higher than normal because of inadequate gas exchange D. His arterial Pco2 is lower than normal because hypoxemia is causing him to hyperventilate E. His residual volume (RV) is decreased

The answer is D [VIII B 2 a]. The patient's arterial Pco2 is lower than the normal value of 40 mm Hg because hypoxemia has stimulated peripheral chemoreceptors to increase his breathing rate; hyperventilation causes the patient to blow off extra CO2 and results in respiratory alkalosis. In an obstructive disease, such as asthma, both forced expiratory volume (FEV1) and forced vital capacity (FVC) are decreased, with the larger decrease occurring in FEV1. Therefore, the FEV1/FVC ratio is decreased. Poor ventilation of the affected areas decreases the ventilation/perfusion (V/Q) ratio and causes hypoxemia. The patient's residual volume (RV) is increased because he is breathing at a higher lung volume to offset the increased resistance of his airways.

A 42-year-old woman with severe pulmonary fibrosis is evaluated by her physician and has the following arterial blood gases: pH = 7.48, PaO2 = 55 mm Hg, and PaCO2 = 32 mm Hg. Which statement best explains the observed value of PaCO2? A. The increased pH stimulates breathing via peripheral chemoreceptors B. The increased pH stimulates breathing via central chemoreceptors C. The decreased PaO2 inhibits breathing via peripheral chemoreceptors D. The decreased PaO2 stimulates breathing via peripheral chemoreceptors E. The decreased PaO2 stimulates breathing via central chemoreceptors

The answer is D [VIII B; Table 4.7]. The patient's arterial blood gases show increased pH, decreased PaO2, and decreased PaCO2. The decreased PaO2 causes hyperventilation (stimulates breathing) via the peripheral chemoreceptors, but not via the central chemoreceptors. The decreased PaCO2 results from hyperventilation (increased breathing) and causes increased pH, which inhibits breathing via the peripheral and central chemoreceptors.

28. A person with a ventilation/perfusion (V/Q) defect has hypoxemia and is treated with supplemental O2. The supplemental O2 will be most helpful if the person's predominant V/Q defect is A. dead space B. shunt C. high V/Q D. low V/Q E. V/Q = 0 F. V/Q = ∞

The answer is D [VII]. Supplemental O2 (breathing inspired air with a high Po2) is most helpful in treating hypoxemia associated with a ventilation/perfusion (V/Q) defect if the predominant defect is low V/Q. Regions of low V/Q have the highest blood flow. Thus, breathing high Po2 air will raise the Po2 of a large volume of blood and have the greatest influence on the total blood flow leaving the lungs (which becomes systemic arterial blood). Dead space (i.e., V/Q = ∞) has no blood flow, so supplemental O2 has no effect on these regions. Shunt (i.e., V/Q = 0) has no ventilation, so supplemental O2 has no effect. Regions of high V/Q have little blood flow, thus raising the Po2 of a small volume of blood will have little overall effect on systemic arterial blood.

The most important feature of acclimation to high altitudes is: a. Polycythemia b. Hyperventilation c. capillary bed increases d. Right sided heart hypertrophy

b. Hyperventilation

Which of the following lung volumes or capacities can be measured by spirometry? A. Functional residual capacity (FRC) B. Physiologic dead space C. Residual volume (RV) D. Total lung capacity (TLC) E. Vital Capacity (VC)

The answer is E [I A 4, 5, B 2, 3, 5]. Residual volume (RV) cannot be measured by spirometry. Therefore, any lung volume or capacity that includes the RV cannot be measured by spirometry. Measurements that include RV are functional residual capacity (FRC) and total lung capacity (TLC). Vital capacity (VC) does not include RV and is, therefore, measurable by spirometry. Physiologic dead space is not measurable by spirometry and requires sampling of arterial Pco2 and expired CO2.

7. Which volume remains in the lungs after a tidal volume (Vt) is expired? A. Tidal volume (Vt) B. Vital capacity (VC) C. Expiratory reserve volume (ERV) D. Residual volume (RV) E. Functional residual capacity (FRC) F. Inspiratory capacity G. Total lung capacity

The answer is E [I B 2]. During normal breathing, the volume inspired and then expired is a tidal volume (Vt). The volume remaining in the lungs after expiration of a Vt is the functional residual capacity (FRC).

6. Which of the following is true during inspiration? A. Intrapleural pressure is positive B. The volume in the lungs is less than the functional residual capacity (FRC) C. Alveolar pressure equals atmospheric pressure D. Alveolar pressure is higher than atmospheric pressure E. Intrapleural pressure is more negative than it is during expiration

The answer is E [II F 2]. During inspiration, intrapleural pressure becomes more negative than it is at rest or during expiration (when it returns to its less negative resting value). During inspiration, air flows into the lungs when alveolar pressure becomes lower (due to contraction of the diaphragm) than atmospheric pressure; if alveolar pressure were not lower than atmospheric pressure, air would not flow inward. The volume in the lungs during inspiration is the functional residual capacity (FRC) plus one tidal volume (Vt).

Hypoxemia produces hyperventilation by a direct effect on the A. phrenic nerve B. J receptors C. lung stretch receptors D. medullary chemoreceptors E. carotid and aortic body chemoreceptors

The answer is E [VIII B 2]. Hypoxemia stimulates breathing by a direct effect on the peripheral chemoreceptors in the carotid and aortic bodies. Central (medullary) chemoreceptors are stimulated by CO2 (or H+). The J receptors and lung stretch receptors are not chemoreceptors. The phrenic nerve innervates the diaphragm, and its activity is determined by the output of the brainstem breathing center.

8. A 35-year-old man has a vital capacity (VC) of 5 L, a tidal volume (Vt) of 0.5 L, an inspiratory capacity of 3.5 L, and a functional residual capacity (FRC) of 2.5 L. What is his expiratory reserve volume (ERV)? A. 4.5 L B. 3.9 L C. 3.6 L D. 3.0 L E. 2.5 L F. 2.0 L G. 1.5 L

The answer is G [I A 3; Figure 4.1]. Expiratory reserve volume (ERV) equals vital capacity (VC) minus inspiratory capacity [inspiratory capacity includes tidal volume (Vt) and inspiratory reserve volume (IRV)].

The oxyhemoglobin dissociation curve is shifted to the left by: a. Increased in temperature b. Increased in pH c. Increased 2,3 DPG d. All of the above

b. Increased in pH

The oxyhemoglobin dissociation curve is shifted to the left by: a. Increased temperature b. Increased pH c. Increased 2,3 DPG d. All of the above

b. Increased pH

Select the respiratory control center from the list that best applies to the description given: This control center consists of three main groups: Medullary respiratory, Apneustic center, and Pneumotaxic center? a. Brainstem group b. Cortex c. Lung receptors d. Central chemoreceptors e. Peripheral chemoreceptors

a. Brainstem group

In order to maintain respiratory functions at higher altitudes: a. Erythropoietin secretion is increased b. Respiratory rate decreases c. Affinity of hemoglobin of oxygen is increased d. None of the above

a. Erythropoietin secretion is increased

In a poorly ventilated alveoli, the physiologic ventilatory-perfusion (V/Q mismatch) abnormality is described as: a. Pulmonary shunt b. Anatomic dead pace c. Physiologic dead space d. Alveolar hyperventilation e. Increased residual volume

a. Pulmonary shunt

A pH disorder with high plasma PCO2: a. Respiratory acidosis b. Respiratory alkalosis c. Metabolic alkalosis d. Metabolic acidosis

a. Respiratory acidosis

How will the lungs compensate for an acute rise in the partial pressure of CO2 in arterial blood? a. Respiratory rate will increase b. Respiratory rate will decrease c. Respiratory membrane permeability will increase d. Respiratory membrane permeability will decrease

a. Respiratory rate will increase

Which of the following conditions would administer oxygen reverse hypoxemia the least? a. Shunt b. Diffusion lost c. Hypoventilation d. V/Q inequality

a. Shunt

Compared with the apex of the lung, the base of the lung has a. A higher pulmonary capillary PO2 b. A higher pulmonary capillary PCO2 c. A higher VQ ratio d. The same VQ ratio

b. A higher pulmonary capillary PCO2

A 25 yo woman with a normal drug function presents with anemia following childbirth (Hemoglobin = 8.6 d/dL). Which of the following parameters is most likely to be reduced? a. Arterial PO2 b. Arterial O2 content c. Right ventricular output d. Minute ventilation

b. Arterial O2 content

With the Bohr effect, more oxygen is released because a(n) a. Decrease in pH (acidosis) strengthens the hemoglobin-oxygen bond b. Decrease in pH (acidosis) weakens the hemoglobin-oxygen bond c. Increase in pH (alkalosis) strengthen the hemoglobin-oxygen bond d. Increase in pH (alkalosis) weakens the hemoglobin oxygen bond

b. Decrease in pH (acidosis) weakens the hemoglobin-oxygen bond

A patient with pulmonary fibrosis asked you to help with the interpretation of his last basic spirometry results. Which of the following will not be included in the report? a. Forced Expiratory volume in 1 sec b. Functional residual capacity c. Vital capacity d. Tidal volume e. Expiratory reserve volume

b. Functional residual capacity

Acid is defined as any substance that adds which of the following to the body fluid? a. Na+ b. H+ c. NaCl d. Cl- e. K+

b. H+

Vital capacity is the sum of: a. Reserve volume + expiratory reserve volume inspiratory reserve volume + tidal volume b. Inspiratory reserve volume+tidal volume + expiratory reserve volume c. Inspiratory reserve volume +tidal volume d. Inspiratory reserve volume +expiratory reserve volume Tidal volume+residual volume

b. Inspiratory reserve volume+tidal volume + expiratory reserve volume

An 18 yo man with insulin-dependent (type 1) diabetes mellitus is seen in the ER. He reports not taking his insulin during the previous 24 hrs because he did not feel well and was not eating. He has the following lab values: pH=7.29 (nml pH=7.35-7.45) [HCO3-} = 12mEq/L; PCO2= 26 mmHg. What kind of acid base disorder does this patient have? a. Respiratory acidosis b. Metabolic acidosis with respiratory compensation c. Respiratory alkalosis d. Metabolic acidosis without respiratory compensation e. Respiratory acidosis with metabolic compensation

b. Metabolic acidosis with respiratory compensation

The patient discovers their forced expiratory volume (FEV) after the first second is 40%. What does this suggest? a. Healthy lungs b. Obstructive pulmonary disease c. Restrictive diseases d. Exposure to asbestos

b. Obstructive pulmonary disease

The Bohr effect refers to the unloading of __________ due to declining blood pH. a. Carbon dioxide b. Oxygen c. BPG d. Chloride ions

b. Oxygen

Which of the choices below determines the direction of respiratory gas movement? a. Solubility in water b. Partial pressure gradient c. The temperature d. Molecular weight and size of the gas molecule

b. Partial pressure gradient

A cerebrovascular tumor that affects forced expirations during rest and exercise most likely damaged which respiratory neural center? a. Apneustic center b. Pneumotaxic center c. Phrenic nerve center d. Dorsal respiratory group e. Ventral respiratory group

b. Pneumotaxic center

Which of the following is incorrect? a. Gas flow equals pressure gradient over resistance b. Pressure gradient equals gas flow over resistance c. Resistance equals pressure gradient over gas flow d. The amount of gas flowing in and out of the alveoli is directly proportional to the difference in pressure or pressure gradient between the external atmosphere and the alveoli

b. Pressure gradient equals gas flow over resistance

Haldane effect is best described as: a. The amount of gas that moves across a sheet of tissue is promotional t te area of the sheet but inversely proportional to the thickness of the sheet b. Removal of oxygen from hemoglobin increases hb affinity for carbon dioxide c. Describes air way resistance d. Pressure inside a spherical structure is directly proportional to tension in wall and inversely proportional to radius of sphere. Surfactant palsy a key role in lung function explained by this law e. Hemoglobin exposed to an environment of low-pressure carbon dioxide results in oxygen being retained by hemoglobin and when exposed to an environment of high pressure of CO2 the hemoglobin releases more oxygen to tissue cells

b. Removal of oxygen from hemoglobin increases hb affinity for carbon dioxide

The lung volume that cannot be measured by spirometry and, thus, needs to be calculated by a different method is: a. Expiratory reserve volume b. Residual capacity c. Inspiratory reserve volume d. Tidal volume e. Lung volume

b. Residual capacity

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 which order: a. Epithelial cell, surfactant, intersitium, endothelial cell, plasma, red cell membrane b. Surfactant, epithelial cell, interstitium, endothelial cell, plasma, red cell membrane c. Epithelial cell, interstitium, endothelial cell, plasma, red cell membrane d. Surfactant, epithelial cell, intersitium, red cell, membrane-endothelial cell

b. Surfactant, epithelial cell, interstitium, endothelial cell, plasma, red cell membrane

Which of the following does NOT happen during inspiration? a. The ribs move upward b. The diaphragm lifts up c. The antero-posterior dimensions of the chest are increased d. The scalene and sternocleidomastoid muscles can be recruited for inspiration

b. The diaphragm lifts up

A fighter pilot who just engaged enemy fighter ina dogfight and whom is returning to base when all of a sudden, his squadron colleagues and control tower traffic controllers notice sudden change in his communication language The most likely explanation for this event is the effect of: a. The effects of positive G forces b. The effects of negative G forces c. The emotional stress of the flight d. Oxygen narcosis

b. The effects of negative G forces

The lung volume that represents the total volume of exchangeable air is the ____________ a. tidal volume b. Vital capacity c. Inspiratory capacity d. Expiratory reserve volume

b. Vital capacity

According to the oxygen-hemoglobin dissociation curve, PO2 in the lungs of 100mmHg results in Hb being 98% saturated. At high altitude, there is less O2. At a PO2 in the lungs of 80 mmHg, Hb would be _______ saturated? a. 98% b. 100% c. 95% d. Less than 50%

c. 95%

Select the respiratory control center from the list that best applies to the description given: MOst important receptors involved in the minute-to-minute control of respiration. Are surrounded by CSF and responds to changes in its H+ concentration. Increase in H+ stimulates ventilation. a. Cortex b. Lung receptors c. Central chemoreceptors d. Peripheral chemoreceptors

c. Central chemoreceptors

Which of the following counteracts the movement of bicarbonate ions from RBC? a. Bohr effect b. Haldane effect c. Chloride shifting d. Release of hydrogen ion

c. Chloride shifting

During extreme exercise, you would likely see what change a. Rise in pH b. Increase in Oxygen binding to hemoglobin c. Decrease in pH d. Decrease in CO2 production

c. Decrease in pH

When a person is standing, blood flow in the lungs is a. Equal at the apex and the base b. Highest at the apex owing to the effects of gravity on arterial pressure c. Highest at the base because that is where the difference between arterial and venous pressure is greatest d. Lowest that the base because that is where alveolar pressure iis greater than arterial pressure

c. Highest at the base because that is where the difference between arterial and venous pressure is greatest

Which of the following conditions would administer oxygen reverse hypoxemia is the best? a. Shunt b. Diffusion loss c. Hypoventilation d. V/Q inequality

c. Hypoventilation

If a patient had a progressive lung disease that required an ever-increasing pressure to fill the same volume of lung, how would the lung's compliance be affected? a. It would increase it b. It would stay the same c. It would decrease it d. These variables do not affect

c. It would decrease it

Which statement about CO2 is FALSE? a. Its concentration in the blood is decreased by hyperventilation b. Its accumulation in the blood is associated with a decrease in pH c. More CO2 dissolves in the blood plasma than is carried in the RBCs d. CO2 concentration are greater in venous blood than arterial blood

c. More CO2 dissolves in the blood plasma than is carried in the RBCs

A scuba diver is using an O2 and CO2 mixture in his tanks. At a depth of approximately 160 ft, his partner notices that the diver no longer responds to hand signals, smiling and offering his mouthpiece to passing fish. The most likely cause for this behavior: a. Oxygen narcosis b. Carbamino narcosis c. Nitrogen narcosis d. Pleased with the dive

c. Nitrogen narcosis

In pulmonary embolism, the physiologic ventilatory/perfusion (V/Q mismatch) abnormality is described as a. Pulmonary shunt b. Anatomic dead space c. Physiologic dead space d. Alveolar hyperventilation e. Increased residual volume

c. Physiologic dead space

A 45-year-old female, who smokes over one pack of cigarettes per day since age 16, comes complaining of progressively worse shortness of breath and easy fatigability. A baseline pulmonary function test is done. Which of the following spirometry findings would you expect in order to confirm the presence of a pulmonary obstructive disorder? a. Increased FEV1/ FVC with a reduced FVC b. Increased FVC with a normal FEV1/FVC c. Reduced FEV1/FVC with a reduced FVC d. Reduced FVC with a normal FEV1/FVC e. Normal FVC with a reduced RV

c. Reduced FEV1/FVC with a reduced FVC

Carbon monoxide poisoning would have what effect on the Hemoglobin dissociation curve? a. Shift to the right with decreased oxygen saturation b. Shift to the left with decreased oxygen saturation c. Shifting to the left with initially then flattening with increased oxygen saturation d. No change

c. Shifting to the left with initially then flattening with increased oxygen saturation

Select the correct statement about oxygen transport in blood. a. During normal activity a molecule of hemoglobin returning to the lung carries one molecule of O2 b. During conditions of acidosis, hemoglobin is able to carry oxygen more efficiently c. Increased BPG levels int her red blood cells enhance oxygen-carrying capacity d. A 50% oxygen saturation level of blood returning to the lungs might indicate an acidity level higher than normal

d. A 50% oxygen saturation level of blood returning to the lungs might indicate an acidity level higher than normal

A young couple decided to move from living near a beach at sea level to Colorado to hike the mountains. As they move their things from the truck into their home, they began to feel dizzy, headache, tiredness, and nausea. What would the likely diagnosis be? a. Chronic respiratory distress b. Chronic mountain sickness c. Acute loss of surfactant d. Acute mountain sickness e. Beach withdrawal

d. Acute mountain sickness

A 40 year old man has a pulmonary embolism that blocks blood flow to his left lung. As a result, which of the following will occur? a. ventilation/perfusion ratio (V/Q) in the left lung would be zero b. Systemic arterial PO2 will be elevated c. V/Q ratio in the left lung will be lower than in the right lung d. Alveolar PO2 in the left lung will be approximately equal to the PO2 in the inspired air e. Alveolar PO2 in the right lung with be approx equal to the PO2 in the venous blood

d. Alveolar PO2 in the left lung will be approximately equal to the PO2 in the inspired air

If you increased the left atrial pressure from 5 mmHg to 15 mmHg, what effect would that have on pulmonary circulation? a. It would force blood the opposite direction b. It would increase the speed at which blood moves through the pulmonary circulation c. No change d. Blood flow would almost or completely stop

d. Blood flow would almost or completely stop

Which letter on the diagram would indicate increased (alveolar) gas pressure?

d. D

Which of the following lab results indicate a partially compensated metabolic alkalosis? a. High pH, low PCO2 and normal bicarbonate b. Low pH, low PCO2 and low bicarbonate c. Low pH, high PCO2 and normal bicarbonate d. High pH, high PCO2 and high bicarbonate

d. High pH, high PCO2 and high bicarbonate

The most important physiologic stimulus controlling the level of resting ventilation: a. PO2 on peripheral chemoreceptors b. PCO2 on peripheral chemoreceptors c. Hydrogen ion concentration on peripheral chemoreceptors d. Hydrogen ion concentration in cerebrospinal Fluid e. PO2 on central chemoreceptors

d. Hydrogen ion concentration in cerebrospinal Fluid

A pH disorder with decreased plasma bicarbonate: a. Respiratory acidosis b. Respiratory alkalosis c. Metabolic alkalosis d. Metabolic acidosis

d. Metabolic acidosis

An experiment was conducted to evaluate the distance of a particle traveling into the airway. The results of the study shows the particle was able to travel up to 16 generations distally into the airway. Where specifically is the particle located? a. Alveolar duct b. Trachea c. Bronchioles d. Terminal bronchioles e. Respiratory bronchioles

d. Terminal bronchioles

Which of the following statements is best representative of pulmonary blood flow? a. Under normal resting conditions, blood flow through the lungs is equal b. Under normal resting conditions, blood flow is diminished in the baes of the lungs c. Under normal resting conditions, blood flow is increased in the apices of the lungs d. Under normal resting conditions, blood flow is diminished in the apices of the lungs

d. Under normal resting conditions, blood flow is diminished in the apices of the lungs

A patient in respiratory distress are evaluated by you at the ER. You notice the patient shows an increase in breathing. You recall the graphic of work breathing as a function of volume above FRC in liters and intrapleural pressure (cmH20). Which area of the graphic represents the total lung work of breathing? a. 0AFCD0 b. AECFA c. ABCEA d. 0AECD0 e. 0ABCD0

e. 0ABCD0

Which of the following is not considered part of Fick's law formula? a. Area (A) b. Diffusion constant (D) c. Thickness (T) or Distance d. Partial Pressure (P) e. Dead Space

e. Dead Space

The CO2 produced by cells is added to venous blood and converted to: a. NaCl and HCO3- b. H2O and H+ c. NaHCO3 and H+ d. H2CO3 and H+ e. H+ and HCO3

e. H+ and HCO3

Bohr effect is best described as: a. The amount of gas that moves across a sheet of tissue is promotional t te area of the sheet but inversely proportional to the thickness of the sheet b. Removal of oxygen from hemoglobin increases hb affinity for carbon dioxide c. Describes air way resistance d. Pressure inside a spherical structure is directly proportional to tension in wall and inversely proportional to radius of sphere. Surfactant palsy a key role in lung function explained by this law e. Hemoglobin exposed to an environment of low-pressure carbon dioxide results in oxygen being retained by hemoglobin and when exposed to an environment of high pressure of CO2 the hemoglobin releases more oxygen to tissue cells

e. Hemoglobin exposed to an environment of low-pressure carbon dioxide results in oxygen being retained by hemoglobin and when exposed to an environment of high pressure of CO2 the hemoglobin releases more oxygen to tissue cells

Select the respiratory control center from the list that best applies to the description given: Located in carotid bodies and aortic bodies. Carotid body most important because it has Glomus cells a. Brainstem group b. Cortex c. Lung receptors d. Central chemoreceptors e. Peripheral chemoreceptors

e. Peripheral chemoreceptors