MCQs on Respiration Physiology With Key

AMNA INAYAT MEDICAL COLLEGE MCQs Test Respiration Physiology TOTAL MARKS: 50,

TOTAL TIME: 50 MINUTES,

DATE: 28-08-13

Q1) A 67-year old man is admitted to Kishwar Fazal Teaching Hospital because of severe chest pain. A catheter is floated into the pulmonary artery, the balloon is inflated and the pulmonary wedge pressure is measured. The pulmonary wedge pressure is used clinically to monitor which of th e following pressures? a. Left atrial pressure  b. Left ventricular pressure c. Pulmonary artery diastolic pressure d. Pulmonary artery systolic pressure e. Systemic capillary pressure Q2). Which of the following sets of differences best describes the hemodynamics of the pulmonary circulation when compared with systemic circulation? Flow Resistance Arterial Pressure a. Higher Higher Higher   b. Higher Lower Lower  c. Lower Higher Lower  d. Lower Lower Lower  e. Same Lower Lower  Q3) The basic rhythm of respiration is generated by neurons located in the medulla. Which of the following limits the duration of inspiration and increases the respiratory rate? a.  b. c. d. e.

Apneustic centre Dorsal respiratory group  Nucleus of the tractus tractus solitaries Pneumotaxic centre Ventral respiratory group

Q4) When the respiratory drive for increased pulmonary ventilation ventilation becomes greater than normal, a special set of respiratory neurons that a re inactive during normal quiet breathing becomes active, contributing to respiratory drive. These neurons are located in which of the following following structures? a.  b. c. d. e.

Apneustic centre Dorsal respiratory group  Nucleus of the tractus tractus solitarius Pneumotaxic centre Ventral respiratory group

Q5 )A healthy, 25 year old medical student participates in a 10-kilometer run to benefit the Pakistan Heart Association. Which of the following following muscles are used during expiration? a.  b. c. d. e.

Diaphragm and external intercostals Diaphragm and internal intercostals Diaphragm only Internal intercostals and rectus abdominis Scalene muscles

Q6) The forces governing the diffusion of a gas through a biological memebrane include the pressure difference across the membrane, the c ross sectional area of the membrane, the solubility of the gas, the distance of diffusion and the molecular weight of the gas. Which of the following changes decrease the diffusion of a gas through a biological membrane? ΔP

a.  b. c. d. e.

Decrease Decrease Decrease Decrease Increase

A

Decrease Decrease Decrease Increase Increase

S

Decrease Decrease Increase Increase Increase

d

Decrease Increase Decrease Decrease Increase

MW

Decrease Increase Decrease Decrease Increase

Q7) The maximum expiratory flow- volume curves in the diagram above were obtained from a healthy individual (curve A) and a 57year old man who complains of  shortness of breath( curve B). which of the following disorders does the man most likely have? a.  b. c. d. e.

Asbestosis Emphysema Kyphosis Scoliosis Silicosis

Q8). A 35year old man remain at high altitude too long and develop chronic mountain sickness. which of the following sets of changes best describes the man with chronic mountain sickness compared with someone living at high altitude who does not develop chronic mountain sickness? Hematocrit a.  b. c. d. e.

Pulmonary Artery Pressure

Decreased Decreased Decreased Increased Increased

Blood Viscosity

Decreased Increased No change Decreased Increased

Decreased Decreased Decreased Increased Increased

Q9). A 32year old man drives to the top of a mountain peak where the Oxygen tension is 85mmHg. Which of the following following best describe de scribe the effects of a hypoxic environment on the pulmonary and systemic vascular resistances? Pulmonary vascular resistance a.  b. c. d. e.

Decreased Decreased Decreased Increased Increased

Systemic vascular resistance Decreased Increased No change Decreased Increased

Q10). The diffusing capacity of a gas is the volume of gas that will diffuse through a membrane each minute for a pressure difference of 1mmHg. Which of the following gases is often used to estimate the oxygen diffusing capacity of the lungs? a.  b. c. d. e.

Carbon dioxide Carbon monoxide Cyanide gas  Nitrogen Oxygen

Q11). The largest change in the PO2 of blood occurs during its transit through which of the following vascular segments under resting conditions? a.  b. c. d. e.

Aorta to pulmonary artery Pulmonary artery to venous end of pulmonary capillary Systemic arterioles arterioles to systemic venules Vena cava to aorta Venous end of pulmonary capillaries to aorta

Q12) : A normal 22year old man breathes in as much air as he can and then exhales as much air as possible. The lung volume at maximum inspiration inspiration is 6.0Litres, and the lung volume after maximum expiration is 1.0Litre. His tidal volume at rest is 0.5Liter, and his functional residual capacity is 3.5Litres. What is his vital capacity? a.  b. c. d. e.

3.0 litres 3.5 litres 4.0 litres 5.0 litres 5.5 litres

Q13): A 72year old woman presents to her physician with dyspnea. Pulmonary function tests revealed an increase rather than decrease in the diffusing capacity of the lung. Which of the following conditions best accounts for an increase in the diffusing capacity? a.  b. c. d. e.

Polycythemia Fibrotic lung disease Pulmonary embolism Congestive heart failure COPD

Q14): Venous admixture a.  b. c. d. e.

Is formed at the level of pulmonary artery Is formed due to venous drainage of lung by pulmonary vein Shunting of blood is not the cause Decrease the PO2 to 95mmHg Increase the PO2 to 104mmHg

Q15).During strenuous exercise, oxygen consumption and carbon dioxide formation can increase upto 20 fold. Alveolar ventilation increases almost exactly in step with this increase in oxygen consumption. Which of the following best describes what happens to the mean arterial oxygen tension PO2, carbon dioxide tension PCO2 and  pH in a healthy athlete during strenuous strenuous exercise? Arterial PO2 a.  b. c. d. e.

Arterial PCO2

Decreased Decreased Increased Increased  No change

Arterial pH

Decreased Increased decreased Increased No change

Decreased Decreased Decreased Increased No change

Q16). A 50 yr old woman is diagnosed with pneumonia that is localized to one lung. Which of the following sets of changes is most likely to be present in this woman compared with a healthy person? Surface area of   pulmonary membrane a.  b. c. d. e.

Decreased Decreased Decreased Decreased Increased

V/Q decreased decreased increased increased decreased

Arterial PCO2

Arterial PO2

decreased increased decreased increased increased

decreased decreased increased decreased decreased

Q17). A hysterical patient is hyperventilating and doubles his alveolar ventilation. The change in his alveolar air will be a.  b. c. d. e.

increase PCO2 by two times decrease PCO2 by half  increase PO2 by two times decrease PO2 by two times decrease PN2 by two times

Q18). What causes the Hb-O2 dissociation curve to shift towards the right side? a.  b. c. d. e.

Increase pH Decrease 2-3 DPG Strenuous exercise Fetal-Hb CO poisoning

Q19). A 42 week gestation infant is delivered by cesarean section. Which of the following occurs with the  baby’s first diaphragmatic respiration? a.  b. c. d. e.

PO2 increases Pulmonary vascular resistance increases Pulmonary capillary hydrostatic pressure increases Systemic vascular resistance decreases All of the fetal vascular channels close

Q20) : A 49 year old coal miner presents with dyspnea and nonproductive cough and decreased exercise tolerance. Lung tests reveal: total lung capacity= 3.34 L (56% of predicted), residual volume = 0.88 L( 54% of predicted and forced vital capacity =1.38 L (30% of predicted). His arterial PO2 is 68 mmHg. Which of the following values will be approximately normal? a.  b. c. d. e.

FEV1/FVC Tidal volume V/Q ratio Diffusing capacity Lung compliance

Q. 21. Which of the following is a function of the lungs? a.  b. c. d. e.

Metabolism Serves as a reservoir of blood for the left ventricle It is a filter to protect the systemic vasculature Facilitates the exchange of O2 and CO2 between air and blood. All of the above are true.

Q.22. Which of the following is the first branching of the bronchial tree that has gas exchanging capabilities? a.  b. c. d. e.

Terminal bronchioles Respiratory bronchioles. Alveoli segmental bronchi alveolar ducts.

Q.23. 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. Q.24. Which of the following concerning average average lung volumes and capacities of a person at rest is TRUE? A. TLC>VC>TV>F T LC>VC>TV>FRC RC B. TLC>FRC>VC>TV TLC>FRC>VC>TV C. TLC>VC>FRC>TV TLC>VC>FRC>TV D. TLC>FRC>TV>VC TLC>FRC>TV>VC Q.25. Which of the following does NOT ha ppen during inspiration? A. The ribs move upward. B. The diaphragm lifts up. C. The antero-posterior dimensions of the chest are increased. D. The tranverse dimensions of the thorax are increased. E. The scalene sca lene and sternocleidomastoid muscles can be recruited for inspiration Q.26. During inspiration, how does alveolar pressure compare to atmospheric pressure? A. Alveolar pressure is greater than atmospheric. B. Alveolar pressure is less than atmospheric. C. Alveolar pressure is the same as atmospheric. D. Alveolar pressure is one of the few pressures where the reference pressure is not atmospheric. Q.27. Which of the following represents the pressure difference that acts to distend the lungs? A. Alveolar pressure B. Airway opening pressure C. Transthoracic pressure D. Transpulmonary pressure E. Esophageal pressure. Q.28. 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 lung compliance. Q.29: A 140 lb woman would have approximately how much dead space in her lungs? A. 140 ml. B. 70 ml. C. 280 ml. D. 35 ml. Q.30: To which of the following is alveolar PCO2 directly proportional? A. Rate of CO2 production and alveolar ventilation. B. Rate of CO2 production and rate of O2 consumption. c onsumption. C. Alveolar ventilation and rate of O2 consumption. D. Alveolar ventilation, rate of O2 consumption, and rate of CO2 production. Q.31: If a patient's blood carries 10 grams of Hb per deciliter, what is the O2 carrying capacity of his blood? A. 18 milliliters per deciliter. B. 20 milliliters per deciliter. C. 10 milliliters per deciliter. D. 13 millliliters per deciliter 

Q.32: Which of the following can cause stagnant hypoxia? A. COPD B. Shock or heart failure. C. Cyanide poisoning. D. Carbon monoxide poisoning. Q.33: If the blood moved slower than normal through the alveolar capillaries, which of the following would have an increased uptake? A. Carbon dioxide. B. Carbon monoxide. C. Oxygen D. nitrogen Q.34: Which of the following is the primary regulating variable of the central chemoreceptors? A. PaO2. B. PaCO2 C. arterial pH D. Input from stretch receptors. Q.35. In which situation would the response to hypoxia be limited? A. In a patient with obstructed airways. B. When hypoxia is acc ompanied by hypercapnea. C. In the hypoxia induced by high altitude. D. During hypoventilation. hypoventilation.

Q.36: Concerning the blood-gas barrier of the human lung: A. The thinnest part of the blood-gas barrier has h as 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 unphysiologically high levels, the blood-gas b arrier can be damaged. E. Oxygen crosses the blood-gas barrier by active transport. Q.37: When oxygen moves through the thin side of the blood-gas blood -gas barrier from the alveolar gas to the hemoglobin of o f 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. Q.38: What is the P O2 (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 Q.39: 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. Q.40 Concerning the blood vessels of the human h uman lung: A. The pulmonary veins form a branching pattern p attern 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 the pu lmonary circulation. D. On the average, blood spends about 0.75 second in the capillaries under resting conditions. E. The mean pressure in the pulmonary artery is about 100 mm Hg. Q.41: If CO2 production remains constant and alveolar ventilation is increased threefold, the alveolar PCO 2 after a steady state is reached will be what percentage of its former value? A. 25 B. 33 C. 50 D. 100 E. 300 Q.42: In a measurement of physiologic dead space using Bohr's method, the alveolar and mixed expired PCO 2 were 40 and 30 mm Hg, respectively. What was the ratio of dead space to tidal volume? A. 0.20 B. 0.25 C. 0.30 D. 0.35 E. 0.40

Q.43: The diffusing capacity of the lung for carbon monoxide is increased 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 sub ject. E. Severe anemia. Q.44: The ratio of total systemic systemic vascular resistance to pulmonary vascular resistance is about: A. 2 : 1 B. 3 : 1 C. 5 : 1 D. 7 : 1 E. 20 : 1 Q.45. 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. Q.46:. 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 d etermined by arterial pressure minus alveolar pressure. E. Blood flow is unaffected by arterial pressure. Q.47: If the pressures in the capillaries 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 Q.48: If helium-oxygen mixtures rather than nitrogen-oxygen mixtures (with the same oxygen concentration) are used for very deep diving: A. Risk of decompression sickness is reduced. B. Work of breathing is increased. C. Airway resistance is increased. D. Risk of O2 toxicity is reduced. E. Risk of inert gas narcosis is increased. Q.49: Which of the following increases by the largest percentage at maximal exercise compared with rest? A. Heart rate. B. Alveolar ventilation. C. PCO2 of mixed venous blood. D. Cardiac output. E. Tidal volume. Q.50: The transition from placental p lacental to pulmonary gas exchange is accompanied by: A. Reduced arterial P O2. B. Rise of pulmonary vascular resistance. C. Closure of the ductus arteriosus. D. Increased blood flow through the foramen ovale. E. Weak respiratory efforts.

AIMCS RESPIRATION REVISION TEST MCQS KEY: DATED: 28-08-13

Q1. A

Q9

D

Q17 B

Q25B

Q33B

Q41B

Q49B

Q2 E

Q10 B

Q18 C

Q26B

Q34B

Q42B

Q50C

Q3 D

Q11 B

Q19 A

Q27D

Q35C

Q43D

Q4 E

Q12 D

Q20 A

Q28C

Q36D

Q44D

Q5 D

Q13 A

Q21 E

Q29A

Q37B

Q45D

Q6

B

Q14 D

Q22B

Q30B

Q38B

Q46D

Q7

B

Q15 E

Q23D

Q31D

Q39E

Q47A

Q8

E

Q16 B

Q24C

Q32B

Q.40D

Q48A