Physiology-Respiratory system MCQs #2
An individual's inspired PO2 was 150 mm Hg and his alveolar PCO2 was 40 mm Hg. If this person's alveolar ventilation then doubled, his alveolar PO2 would be expected to change by: (assume a new steady state and an R value of 1.0) (A) 20 mm Hg (B) 25 mm Hg (C) 40 mm Hg (D) 50 mm Hg (E) No change
A
Select the lettered arrow that corresponds to total lung capacity (TLC)
A
What changes in lung function occur as a result of a (right) pneumothorax? (A) The intrapleural pressure in the affected area equals to atmospheric pressure. (B) The chest wall on the affected side recoils inward. (C) There is hyperinflation of the affected lung. D) The V/Q ratio on the affected side increases above normal. (E) The mediastinum shifts further to the right with each inspiration.
A
Which of the following laboratory values is consistent with pulmonary fibrosis? (A) Decreased diffusing capacity of the lung (B) Increased residual volume (C) Decreased FEV1/FVC (D) Increased lung compliance (E) Increased airway resistance corrected for lung volume
A
At which point on the flow-volume loop pictured below will airflow remain constant despite an increased respiratory effort?
B
At what time is transpulmonary pressure greatest? (A)0 seconds (B) 1 seconds (C) 2 seconds (D)3 seconds (E) 4 seconds
C
Comparing a premature infant with respiratory distress syndrome to a normal full-term infant, how do lung compliance and surfactant levels compare? Compliance in Preterm VS Full Surfactant in Preterm Term Infant Compared to Full Term Infant (A) ↑ ↓ (B) ↑ ↑ (C) ↓ ↓ (D) ↓ ↑ (E) ↔ ↑ (F) ↔ ↓
C
Select the lettered arrow that corresponds to forced expiratory volume in 1 second (FEV1)
C
Select the lettered arrow that corresponds to vital capacity (VC)
D
The inherent rhythm for respiration appears to be located within the: (A) Apneustic center (B) Upper pons (C) Lower pons (D) Medulla
D
A man breathing at a frequency of 20 breaths per minute has a minute ventilation of 8 L/min and a dead space of 150 mL. His alveolar ventilation is: (A)250 mL/min (B) 400 mL/min (C) 2,500 mL/min (D)3,000 mL/min (E) 5,000 mL/min
E
Airway resistance can be reduced by... (A)Increasing vagal impulses to the lungs (B) Administering a p-adrenergic blocking drug (C) Decreasing the radial traction exerted by lung tissue (D)Performing a maximal forced expiration (E) Increasing lung volume
E
Both the peripheral and the central chemoreceptors mediate increased ventilation in response to which of the following? (A) Acute hypercapnia (B) Acute metabolic acidosis (C) Chronic hypercapnia (D) Chronic hypertension (E) Chronic hypoxemia
A
During a forced expiration, a patient generates an intrapleural pressure of 20 mm Hg. The patient's equal pressure point will move closer to the mouth and forced expiratory volume will increase if there is an increase in which of the following? (A) Inspired lung volume (B) Lung compliance (C) Airway resistance (D) Expiratory effort (E) Airway smooth muscle tone
A
Resistance in the airways of the lungs decreases: (A) In response to sympathetic nerve stimulation (B) In response to parasympathetic nerve stimulation (C) In response to a decrease in alveolar PCO2 (D) As the diameter of the air tubes decreases (E) As the velocity of airflow increases
A
The activity of the central chemoreceptors is stimulated by which of the following? (A) An increase in the PCO2 of blood flowing through the brain (B) A decrease in the PO2 of blood flowing through the brain (C) An increase in the pH of the CSF (D) A decrease in the metabolic rate of the surrounding brain tissue (E) Hypoxemia, hypercapnia, and metabolic acidosis
A
The concentration of CO2 is lowest in the: (A)Anatomical dead space at end inspiration (B) Anatomical dead space at end expiration (C) Alveoli at end inspiration (D)Alveoli at end expiration (E) Blood in the pulmonary veins
A
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
A
The volume of N2 dissolved in body fluids is greatest while breathing which of the following gas mixtures? (A)Air at sea level (B) Air at an altitude of 15,000 feet (C) 20% O2, 20% N2, 60% He, while scuba diving at 2 atm of pressure (D)20% O2, 30% N2, 50% He, while scuba diving at 2 atm of pressure (E) 20% O2, 10% N2, 70% He, while scuba diving at 5 atm of pressure
A
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
A
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
A
A 14-year-old adolescent girl presents with a lump in the neck. Fine needle aspiration biopsy reveals acinic cell carcinoma of the parotid gland. During the parotidectomy, there is compression injury of the glossopharyngeal nerve. As a result, which of the following respiratory reflexes will be impaired? (A) Aortic chemoreceptor reflex (B) Carotid body chemoreceptor reflex (C) Hering-Breuer inflation reflex (D) Irritant airway reflex (E) Juxta pulmonary capillary (J) receptor reflex
B
A 36-year-old woman is found comatose at her home and is life-flighted to the nearest regional medical center. Blood gases reveal a normal PaO2 but a lower-than-normal arterial O2 saturation. Which of the following conditions is most consistent with the findings? (A) Anemia (B) Carbon monoxide poisoning (C) Hypoventilation (D) Low V/Q ratio (E) Right-to-left shunt
B
A 58-year-old woman experiences an acute exacerbation of asthma, which causes her breathing to become labored and faster. As a result, which of the following changes in airflow is expected? (A) Flow in the trachea and upper airways will become more laminar. (B) The pressure gradient required for airflow will increase. (C) The resistance to airflow will decrease. (D) The resistance to airflow will increase linearly with the decrease in airway radius (E) Reynolds number will decrease.
B
A 66-year-old male with a long history of cigarette smoking complains of difficulty breathing and a persistent cough productive of thick mucus. Pulmonary function tests on this patient reveal increased total lung capacity (TLC) and residual volume (RV), a normal vital capacity (FVC), a reduced FEV1, and a FEV1/FVC ratio of 0.58. This spirometric pattern is most consistent with which of the following? (A)A decreased pulmonary diffusion capacity (B) An obstructive lung disease only (C) A combination of restrictive and obstructive lung disease (D)A restrictive lung disease only (E) A normal pattern with no evidence of either restrictive or obstructive lung disease
B
A decrease in blood pH will displace the hemoglobin dissociation curve to the: (A) Right and reduce O2 carrying capacity (B) Right with no change in O2 carrying capacity (C) Left and reduce O2 carrying capacity (D) Left with no change in O2 carrying capacity
B
After living at an altitude of 3,500 meters for two months, a subject will have: (A) Higher than normal arterial PCO2 (B) Elevated hematocrit (C) Abnormally low pressure in the pulmonary artery (D) Elevated erythropoietin
B
An elderly male patient with thrombophlebitis in one leg develops a pulmonary embolus that completely blocks blood flow to the upper lobe of his left lung. Which one of the following would most likely increase as a result? (A)Functional residual capacity (FRC) (B) Physiological dead space (C) FEV1/FVC ratio (D)Physiological shunt flow (E) Residual volume (RV)
B
An increase in the activity of the afferent nerves associated with the Hering-Breuer reflex would indicate: (A) Expiration is occurring (B) Inspiration is occurring (C) A decreasing blood volume with the pulmonary vasculature (D) Pulmonary congestion
B
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
B
At a fraternity party a 17-year-old male places a paper bag over his mouth and breathes in and out of the bag. As he continues to breathe into this bag, his rate of breathing continues to increase. Which of the following is responsible for the increased ventilation? (A) Increased alveolar Po2 (B) Increased alveolar Pco2 (C) Decreased arterial Pco2 (D) Increased pH
B
Compared to a normal healthy person, how do total lung capacity and maximal expiratory flow patient change with restrictive lung disease? Total lung capacity Maximum expiratory flow (A) ↑ ↓ (B) ↓ ↓ (C) ↑ ↑ (D) ↓ ↑
B
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
B
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
B
During inspiration (as compared to expiration): (A) Intrapleural pressure is increasing (B) Lung recoil is increasing (C) Abdominal muscles are normally contracting (D) Both A and B are correct (E) All of the above are correct
B
During the effort-independent portion of a forced vital capacity (EVC) maneuver, the expiratory flow rate... (A)Varies as a function of the interpleural pressure (B) Is limited by compression of the airways (C) Depends on the alveolar pressure (D)Is maximal for that individual (E) Is constant
B
If a person inspires maximally, closes his glottis, and contracts his expiratory muscles as hard as he can (Valsalva maneuver): (A) Intrapleural pressure is higher than alveolar pressure (B) Intrapleural pressure and lung recoil both act to increase pressure within the alveoli (C) Intrapleural pressure is below atmospheric at the apex but above atmospheric at the base (D) All of the above are correct (E) None of the above are correct
B
If the graph holds true for a patient breathing over a period of a minute what is the closest approximate to their alveolar minute ventilation (assuming a dead space of 200 ml). (A)2.5 L/min (B) 4 L/min (C) 6.5 L/min (D)8 L/min (E) Cannot be determined from this graph.
B
In a maximal expiration, the total volume expired is (A) Tidal volume (TV) (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
B
In which vascular bed does hypoxia cause vasoconstriction? (A) Coronary (B) Pulmonary (C) Cerebral (D) Muscle (E) Skin
B
Most of the carbon dioxide carried by the blood is: (A) Dissolved as CO2 (B) Plasma bicarbonate (C) Red blood cell bicarbonate (D) Carbamino compounds, (E) Combined with plasma proteins
B
Pulmonary edema in CHF is promoted by which of the following? (A) Decreased pulmonary interstitial oncotic pressure (B) Increased pulmonary capillary hydrostatic pressure (C) Increased pulmonary capillary oncotic pressure (D) Increased pulmonary interstitial hydrostatic pressure (E) Decreased pulmonary capillary permeability
B
Select the lettered arrow that corresponds to functional residual capacity (FRC)
B
The peripheral chemoreceptors for oxygen (in carotid and aortic bodies) increase their rate of discharge primarily in response to: (A) A decrease in blood oxygen content (B) A decrease in the partial pressure of blood oxygen (C) A decrease in blood H+ concentration (D) A decrease in dissolved oxygen in cerebral spinal fluid (E) An increase in percent saturation of hemoglobin with oxygen
B
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
B
Which of the following clinical or laboratory findings best reveals the presence of a hypoxic ventilatory response in a patient with arterial hypoxemia? (A)Increased anion gap (B) Decreased arterial PCO2 (C) Increased plasma bicarbonate (D)Decreased plasma pH (E) Increased A-a PO2 difference
B
Which of the following statements regarding the normal alveolar CO2 tension is true? (A)It is equal in all alveoli (B) It is highest at the base of vertical lungs (C) It is directly proportional to the inspired O2 tension (D)It is directly proportional to the alveolar ventilation (E) It is equal to 46 mm Hg
B
Which of the following will decrease the oxygen consumption of the respiratory muscles? (A) A decrease in lung compliance (B) A decrease in airway resistance (C) A decrease in the diffusing capacity of the lung (D) An increase in the rate of respiration (E) An increase in tidal volume
B
Which one of the following statements best characterizes lung compliance? (A) It is equivalent to △P/△V. (B) It is inversely related to the elastic recoil properties of the lung. (C) It decreases with advancing age. (D) It increases when there is a deficiency of surfactant. (E) It increases in patients with pulmonary edema
B
A 27-year-old man develops adult respiratory distress syndrome (ARDS) after near-drowning. Conventional mechanical ventilation on 100% O2 together with inhaled nitric oxide do not provide sufficient oxygenation. Porcine surfactant is instilled via fiberoptic bronchoscope, and the PaCO2, fraction of inspired oxygen (FIO2), and shunting improve impressively. The improvements in respiratory function occurred because surfactant increased which of the following? (A) Bronchiolar smooth muscle tone (B) The pressure gradient needed to inflate the alveoli (C) Lung compliance (D) Alveolar surface tension (E) The work of breathing
C
A deficiency of pulmonary surfactant would: (A)Decrease surface tension in the alveoli (B) Decrease the change in intrapleural pressure required to achieve a given tidal volume (C) Decrease lung compliance (D)Decrease the work of breathing (E) Increase functional residual capacity (FRC)
C
A lack of normal surfactant, as occurs in infants with respiratory distress syndrome (RDS), results in... (A)Increased lung compliance (B) Stabilization of alveolar volume (C) Increased retractive force of the lungs (D)Reduced alveolar-arterial O2 tension difference (E) Decreased filtration forces in the pulmonary capillaries
C
A medical student waiting to do her first patient interview at the clinical skills center becomes very anxious and increases her rate of alveolar ventilation. If her rate of CO2 production remains constant, which of the following will decrease? (A) pH (B) PaO2 (C) PaCO2 (D) V/Q (E) Alveolar-arterial PO2 difference
C
A patient comes into your office complaining of shortness of breath. He weighs 360 lbs is a non-smoker and has had no medical history of relevance. Which of the following changes, in any, would you expect to occur? (A)An increase in FRC due to an increase in lung compliance (B) A decrease in FRC due to a decrease in lung compliance (C) A decrease in FRC due to a decrease in chest wall recoil (D)An increase in FRC due to an increase in chest wall recoil (E) None of the above would be observed
C
A patient is on a ventilator adjusted for an inspiratory tidal volume of 1 L at a frequency of 10 b/min. If the patient's anatomic dead space is 200 mL and the machine's dead space 50 mL, the patient's alveolar ventilation is: (A)10 L/min (B) 8.0 L/min (C) 7.5 L/min (D)5 L/min (E) Not determinable from the information given
C
A patient with restrictive lung disease (RLD) typically has... (A)An increased forced expiratory volume in 1 second (FEV1) and a normal lung compliance (B) A decreased FEV1 and an increased lung compliance (C) A decreased FEV1 and a decreased lung compliance (D)An increased FEV1 and an increased lung compliance (E) An increased FEV1 and a decreased lung compliance
C
A person starts to breathe from a 12 L spirometer containing 10% helium at the end of a passive expiration. If, after several minutes, the helium concentration in the spirometer falls to 8% this person's functional residual capacity (FRC) is approximately: (A)1.2 L (B) 2.4 L (C) 3.0 L (D)4.0 L (E) 4.8 L
C
An 83-year-old woman is found unresponsive by her son approximately 3 hours after her gall bladder surgery. The nurse reported that the patient had asked for her pain meds and said she was going to rest for a while. Arterial blood gases reveal hypercapnia and hypoxemia. Which of the following is the most likely cause of the high arterial PCO2? (A) Decreased metabolic activity (B) Decreased alveolar dead space (C) Hypoventilation (D) Hypoxemia (E) V/Q inequality
C
During inspiration, as the diaphragm contracts, the pressure in the interpleural space becomes... (A)Equal to zero (B) More positive (C) More negative (D)Equal to the pressure in the alveoli (E) Equal to the pressure in the atmosphere
C
Hypercapnia affects respiration primarily by stimulating the... (A)Carotid and aortic bodies (B) Receptors (C)Central (medullary) chemoreceptors (D)Arterial baroreceptors (E) Hypoglossal nerve
C
If surfactant is absent from the alveoli, the lungs': (A) Airway resistance will decrease (B) Compliance will increase (C) Compliance will decrease (D) O2 diffusing capacity will increase (E) Recoil will decrease
C
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
C
Maximal inspiratory gas flow occurs when the... (A)Lung volume approaches total lung capacity (TLC) (B) Lung volume approaches residual volume (RV) (C) Alveolar pressure is most negative (D)Interpleural pressure is approximately - 5 cm H2O (E) Abdominal muscles are maximally contracted
C
Normally, intrapleural pressure is negative throughout a tidal inspiration and expiration because of which of the following? (A) The lungs have the tendency to recoil outward throughout a tidal breath. (B) The chest wall has the tendency to recoil inward throughout a tidal breath. (C) The intact pleura causes the lungs and chest wall to recoil away from each other throughout a tidal breath. (D) The intact pleura causes the lungs and chest wall to recoil in the same direction throughout a tidal breath. (E) There is always a small leak in the visceral pleura causing some air to escape into the pleural space during a tidal breath
C
Taking a deep inspiration to total lung capacity causes which of the following cardiopulmonary function variables to increase? (A) Alveolar surface tension (B) Airway resistance (C) Elastic recoil of the lung (D) Intrapleural pressure (E) Lung compliance
C
The following pressure-volume curves were obtained from subjects X and Y during quiet breathing at a rate of 14/min. What conclusion can you draw from these curves? Subject X has the: (A) Higher pulmonary compliance (B) Higher tidal volume (C) Higher pulmonary compliance and tidal volume (D) Lower pulmonary compliance (E) Lower pulmonary compliance and tidal volume
C
The major area of airway resistance during breathing is located in the... (A)Oropharynx (B) Trachea and large bronchi (C) Intermediate-sized bronchi (D)Bronchioles < 2 mm in diameter (E) Alveoli
C
The major sign of hypoventilation is... (A)Cyanosis (B) Increased airway resistance (C) Hypercapnia (D)Dyspnea (E) Hypoxia
C
The ventilatory capacity of a patient with respiratory disease is evaluated using spirometry. Which of the following is the correct spirometric term for the largest exhaled volume that this patient can generate during the course of pulmonary function testing? (A)Total lung capacity (TLC) (B) Inspiratory capacity (IC) (C) Forced vital capacity (FVC) (D)Inspiratory reserve volume (IRV) (E) FEV1
C
The volume of gas in the lungs at the end of a normal expiration is referred to as the... (A)Residual volume (RV) (B) Expiratory reserve volume (ERV) (C) Functional residual capacity (FRC) (D)Inspiratory reserve volume (IRV) (E) Total lung capacity (TLC)
C
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
C
When all ventilatory muscles are relaxed, the volume in the lungs is at: (A)Residual volume (RV) (B) Expiratory reserve volume (ERV) (C) Functional residual capacity (FRC) (D)Inspiratory reserve volume (IRV) (E) Total lung capacity (TLC)
C
Which of the following best represents the systemic arterial blood of an individual with anemia? (A) Low PO2, low hemoglobin, normal O2 content (B) Low PO2, low hemoglobin, low O2 content (C) Normal PO2, low hemoglobin, low O2 content (D) Normal PO2, normal hemoglobin, low O2 content (E) Low PO2, normal hemoglobin, low O2 content
C
Which of the following conditions will cause a decrease in pulmonary vascular resistance? (A) Alveolar hypoxia (B) Decreased pH in the pulmonary artery (C) Increased cardiac output (D) Inflation of the lungs to total lung capacity (E) Sympathetic stimulation of the pulmonary vessels
C
Which of the following could produce a decrease in alveolar ventilation with no change in total ventilation? (A) A decreased functional residual capacity (B) A decreased respiratory rate and tidal volume (C) An increased respiratory rate and decreased tidal volume (D) A decreased respiratory rate and increased tidal volume (E) An increased respiratory rate and tidal volume
C
Which of the following formulas is correct? (A) Vital capacity = inspiratory volume + expiratory reserve volume (B) Dead air space = resting tidal volume + residual volume (C) Alveolar ventilation = (respiratory rate) × (tidal volume - dead air space) (D) Vital capacity = inspiratory reserve volume + resting tidal volume + expiratory reserve volume + residual volume (E) Inspiratory reserve volume = vital capacity - resting tidal volume
C
Which of the following is higher at the apex of the lung than at the base when a person is upright? (A) Ventilation (B) Blood flow (C) V/Q ratio (D) PaCO2 (E) Lung compliance
C
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
C
Which of the following statements best characterizes the pattern of ventilation in the lungs during quiet breathing? (A) Surfactant keeps each region of the lung equally distended and ventilated. (B) Gravity in the erect individual keeps the base of the lung more poorly expanded and it receives less ventilation than the apex. (C) Gravity in the erect individual keeps the base of the lung more poorly expanded but it receives more ventilation than the apex. (D) Gravity in the erect individual keeps the base of the lung more expanded and ventilated than the apex. (E) Gravity in the erect individual keeps the base of the lung more expanded and less ventilated than the apex.
C
At which one of the following lung volumes/capacities is transpulmonary pressure at its greatest? (A)Residual volume (B) Functional residual capacity (C) Total lung capacity (D)When breathing at rest (E) After taking a deep breath prior to diving into water
C & E
. If alveolar PCO2 was originally 40 mm Hg but body temperature increased and CO2 production doubled while no change occurred in alveolar ventilation, what decrease should occur in alveolar PO2? (Assume R = 1.0) (A) 10 mm Hg (B) 20 mm Hg (C) 30 mm Hg (D) 40 mm Hg (E) No change
D
A 12-year-old boy has a severe asthmatic attack with wheezing. He experiences rapid breathing and becomes cyanotic. His arterial PO2 is 60 mmHg and his PCO2 is 30 mmHg. Which of the following statements about this patient is most likely to be true? (A) Forced expiratory volume/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
D
A 125-lb, 40-year-old woman with a history of nasal polyps and aspirin sensitivity since childhood presents to the emergency department with status asthmaticus and hypercapnic respiratory failure. She requires immediate intubation and is placed on a mechanical ventilator on an FIO2 of 40%, a control rate of 15 breaths/min, and a tidal volume of 500 mL. Which of the following is her approximate alveolar ventilation? (A) 375 mL/min (B) 3,500 mL/min (C) 5,250 mL/min (D) 5,625 mL/min (E) 7,500 mL/min
D
A 37-year-old woman is admitted to the hospital with severe kyphoscoliosis and respiratory muscle weakness. Which of the following physiological variables is most likely decreased in this patient? (A) Airway resistance (B) Alveolar surface tension (C) Arterial carbon dioxide tension (D) Chest wall compliance (E) FEV1/FVC
D
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
D
A 45-year-old man inhaled as much air as possible and then expired with a maximum effort until no more air could he expired. This produced the maximum expiratory flow-volume curve shown in the following diagram. What is the forced vital capacity of this man (in liters)? (A) 1.5 (B) 2.5 (C) 3.5 (D) 4.5 (E) 5.5 (F) 6.5
D
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
D
A healthy 65-year-old man with a tidal volume (TV) of 0.45 L has a breathing frequency of l6 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
D
Airway resistance is greater... (A) With laminar flow than with turbulent flow (B) At lower values for Reynolds number (C) During inspiration compared to expiration (D) At low lung volumes compared to high lung volumes (E) In the total cross section of the small airways compared to the total cross section of the central airways
D
Alveolar ventilation is equal to the... (A)Dead space ventilation (B) Tidal volume times respiratory rate (C) Minute ventilation (D)Minute ventilation minus dead space ventilation (E) CO2 production/min
D
An emphysematic patient comes to your office complaining of difficulty in breathing. You encourage him to exhale through pursed lips as this will help him by: (A)Moving the EPP closer to his alveoli (B) Increasing the compliance of his lungs (C) Keeping the oxygen tube in his mouth (D)Decreasing the pressure gradient between the alveoli and trachea (E) Decreasing the compliance of his lungs
D
In a healthy human subject, either at rest or during exercise, most of the carbon dioxide transported from the peripheral tissues to the lungs is in which of the following forms? (A)Carbaminohemoglobin (B) Dissolved CO2 (C)Carbonic acid (D)Bicarbonate (E) Carboxyhemoglobin
D
In a normal individual, respiration (alveolar ventilation) is regulated mainly via: (A) Peripheral chemoreceptors responding to changes in PO2 (B) Peripheral chemoreceptors responding to changes in PCO2 (C) Central chemoreceptors responding to changes in PO2 (D) Central chemoreceptors responding to changes in PCO2 (E) Central chemoreceptors responding to changes in both PCO2 and PO2
D
In the below figure, if curve N represents the oxygen-Hb dissociation curve of a normal individual, then curve A represents: (A) Polycythemia and B represents anemia (B) Anemia and B represents polycythemia (C) Anemia and B represents carbon monoxide poisoning (D) Carbon monoxide poisoning and B represents anemia (E) Carbon monoxide poisoning and B represents polycythemia
D
Increasing the tidal volume while keeping everything else constant increases the... (A)Dead space ventilation (B) Functional residual capacity (FRC) (C) Inspiratory capacity (D)Alveolar ventilation (E) Alveolar CO2 tension
D
Oxygen therapy is most beneficial in which of the following situations? Assume lung function is normal. (A) Anemia (B) CO2 retention (COPD) (C) Cyanide poisoning (D) High altitude
D
The figure below represents the inflation pressure-volume curve of three different lungs. If the middle curve represents a normal lung, which of the following statements is correct? (A) The compliance of lungs A and B are both greater than normal. (B) Lung A is more compliant than normal, and at any lung volume recoil will be greater than in normal lungs. (C) Lung B is more compliant than normal, and at any given lung volume recoil will be greater than in normal lungs. (D) Lung A is more compliant than normal, and for a given change in surrounding pressure, a greater change in lung volume will occur than in normal lungs. (E) Lung B is more compliant than normal, and for a given change in surrounding pressure, a greater change in lung volume will occur than in normal lungs.
D
The maximum expiratory flow-volume curve shown in the following diagram is used as a diagnostic tool for identifying obstructive and restrictive lung diseases. At which of the following points on the curve does airway collapse limit maximum expiratory air flow?
D
The respiratory system is at the equilibrium position in all of the following conditions EXCEPT... (A)At the end of a normal expiration (B) When the transrespiratory pressure is zero (C) When lung recoil is balanced by chest wall expansion (D)When lung volume is at residual volume (RV) (E) When the respiratory muscles are relaxed and the airway is open
D
The vital capacity (VC) is the sum of the... (A)Residual volume (RV), tidal volume, and expiratory reserve volume (ERV) (B) RV, tidal volume, and inspiratory reserve volume (IRV) (C)RV, ERV, and IRV (D)ERV, IRV, and tidal volume (E) Functional residual capacity (FRC) and inspiratory capacity
D
Which of the following is illustrated in the graph showing volume versus pressure in the lung-chest wall system? (A) The slope of each of the curves is resistance (B) The compliance of the lungs alone is less than the compliance of the lungs plus chest wall (C) The compliance of the chest wall alone is less than the compliance of the lungs plus chest wall (D) When airway pressure is zero (atmospheric), the volume of the combined system is the functional residual capacity (FRC) (E) When airway pressure is zero (atmospheric), intrapleural pressure is zero
D
Which of the following regarding the transmural pressure for the lungs is true? (A)It is always negative (B) It is equal to the interpleural pressure minus the atmospheric pressure (PPL - PB) (C) It is equal to the interpleural pressure minus the alveolar pressure (PPL - PA) (D)It is equal to the alveolar pressure minus the interpleural pressure (PA - PPL) (E) It is independent of lung volume when the muscles are relaxed
D
Which of the following will decrease the O2 carrying capacity of blood? (A) Increased PCO2 (B) Increased temperature (C) Decrease in pH (D) Decreased hemoglobin
D
Which of the following will increase as a result of stimulating cholinergic receptors on the bronchial smooth muscle? (A) Lung compliance (B) Airway diameter (C) Elastic work of breathing (D) Resistive work of breathing (E) Anatomic dead space
D
Which volume remains in the lungs after a maximal expiration? (A) Tidal volume (TV) (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
D
A 35-year-old woman with gestational diabetes develops hypertension and preeclampsia, requiring the preterm delivery of her fetus of 30-weeks' gestation. The mother is given two doses of betamethasone, 12 mg, intramuscularly, 24 hours apart. Which of the following is the purpose of the antenatal steroid therapy? (A) Increase fetal PO2 (B) Increase blood flow to the fetal lungs (C) Shift the fetal oxyhemoglobin dissociation curve to the right (D) Increase blood flow from the right atrium into the left atrium across the foramen ovale (E) Increase the lecithin/sphingomyelin ratio in the amniotic fluid
E
A 46 year old male during quiet breathing has an intrapleural pressure is about - 5 cm H2O at the start of inspiration (relative to atmospheric pressure). As inspiration proceeds to a full normal tidal breath, transmural pressure between the alveoli and the pleural space reaches approximately: (A)- 10 cm H2O (B) - 1 cm H2O (C) 0 cm H2O (D)+ 1 cm H2O (E) + 10 cm H2O
E
A 78-year old man who smoked 60 cigarettes per day for 55 years complains of shortness of breath. The patient is diagnosed with chronic pulmonary emphysema. Which of the following sets of changes is present in this man, compared to a healthy, nonsmoker? Pulmonary Compliance Lung Elastic recoil Total Lung Capacity (A) Decreased Decreased Decreased (B) Decreased Decreased Increased (C) Decreased Increased Increased (D) Increased Decreased Decreased (E) Increased Decreased Increased (F) Increased Increased Increased
E
A hospitalized patient has tachypnea and significantly labored respirations requiring mechanical ventilation. Based on the pressure-volume curve of the lungs shown as curve Z in the figure below, which of the following is the most likely diagnosis for the patient? (A) Asthma (B) Emphysema (C) Dyspnea with aging (D) Newborn with lecithin to sphingomyelin (L/S) ratio greater than 2 (E) Pulmonary edema
E
A spirometer can be used to directly measure which of the following? (A) Functional residual capacity (B) Peak flow rate (C) Residual volume (D) Total lung capacity (E) Vital capacity
E
A young child inhales a marble that lodges in the airway supplying the lower lobe of the right lung, completely blocking the ventilation of this part of the lung. Which one of the following would most likely increase as a result? (A)Anatomical dead space (B) Anatomical shunt flow (C) Azygos vein flow (D)Physiological dead space (E) Physiological shunt flow
E
All of the following can reduce vital capacity (VC) EXCEPT... (A)Decreased total lung capacity (TLC) (B) Increased residual volume (RV) (C) Weakness of the inspiratory muscles (D)Weakness of the expiratory muscles (E) Decreased alveolar surface tension
E
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
E
Immediately upon arriving at a ski resort located 11,500 feet above sea level, a healthy sea-level native would experience an increase in resting minute ventilation, most likely due to which of the following? (A)The effect of low arterial PO2 on central chemoreceptors (B) The effect of increased arterial PCO2 on central chemoreceptors (C) The CNS ischemic reflex (D)The effect of increased arterial PCO2 on peripheral chemoreceptors (E) The effect of low arterial PO2 on peripheral chemoreceptors
E
In the patient's spirometry tracing below, the expiratory reserve volume equals which of the following? (A) C (B) D (C) E (D) C + D (E) E - D
E
Reduction of functional hemoglobin associated with anemia, methemoglobinemia, or carbon monoxide poisoning does not produce an increased respiratory rate because the: (A)Blood flow to the carotid body is unchanged (B) Arterial oxygen content is maintained within the normal range (C)Carotid body chemoreceptors are stimulated (D)SaO2 of arterial blood is normal (E) PaO2 of arterial blood is normal
E
Select the lettered arrow that corresponds to residual volume (RV)
E
The pacemaker neurons responsible for respiratory rhythmogenesis are located in which of the following regions of the brain? (A) Apneustic center in the pons (B) Central chemoreceptors in the medulla (C) Inspiratory neurons in the dorsal respiratory group (D) Pontine respiratory groups (E) Pre-Botzinger complex in the ventral respiratory group
E
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
E
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)
E
Which one of the following statements regarding the compliance of the respiratory system is true? (A)It is greater than the compliance of the chest wall (B) It is greater than the compliance of the lungs (C) It is equal to the compliance of the chest wall (D)It is equal to the compliance of the lungs (E) It is less than the compliance of the chest wall
E
Which volume remains in the lungs after a tidal volume (TV) is expired? (A) Tidal volume (TV) (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
E
A 35-year-old man has a vital capacity (VC) of 5 L, a tidal volume (TV) 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
G
