Uploaded by Mureithi Joseph Gichuhi

Physiology Yr2.4

This test consists of fifty (50) compulsory multiple choice questions. Each question
consists of a common stem that gives rise to four responses (A – D).
In every question identify the MOST CORRECT (BEST RESPONSE) answer
and mark it on the answer sheet using the sign (X).
ONLY ONE answer is correct in each question.
Each correct response earns one (+1) mark, an incorrect response and an unmarked
response each earns zero (0) mark.
Enter your responses clearly in the answer sheet provided.
Enter your university registration number in the space provided on the answer sheet. DO NOT
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1. The rate of gas diffusions across the respiratory membrane is determined by the
following EXCEPT
a. Membrane thickness
b. Surface area of the membrane
c. Diffusion coefficient of the gas
d. Total lung capacity
2. Dalton’s law with regard to gases describes:
a. The principles of gas expansion
b. The laws of partial pressures of gases
c. Solubility of gas in solution
d. The laws of temperature difference between partial gases
3. Fick’s law of diffusion relates:
a. Diffusion and surface area
b. Diffusion and membrane length
c. Diffusion and pore diameter
d. Diffusion and water content
4. The ventilation perfusion ratio
a. Measurement is based on PO2 and pulmonary blood flow rate
b. Normal value is 1
c. When its value is zero implies lack of perfusion
d. Decreases from the base to the apex of the lung
5. Regarding ventilation and perfusion
a. Ventilation increases towards the base of the lungs
b. Perfusion increases towards the apex of the lungs
c. The V/Q ratio is greater at the apex than at the base
d. Normal alveolar ventilation averages 60L/minute
6. When the ventilation perfusion ratio is zero
a. The alveolar PO2 equilibrates with that of inspired air
b. It results from pulmonary embolism
c. The alveolar PO2 equilibrates with that of pulmonary capillary blood
d. It results from reduced cardiac output
7. When the ventilation perfusion ratio equals to infinity
a. The alveolar PO2 equilibrates with that of inspired air
b. It results from alveolar collapse
c. The alveolar PO2 equilibrates with that of pulmonary capillary blood
d. It results from reduction in alveolar ventilation
8. An increase in altitude causes a decrease in gas exchange efficiency because
a. Less blood circulates through the lungs
b. The surface area of the alveoli decreases
c. Partial pressure of oxygen in inspired air decreases
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d. At high altitude there are low levels of 2,3 DPG
9. Concerning myoglobin
a. Takes up oxygen from hemoglobin
b. Is also found in circulation
c. Is an iron containing pigment found only in smooth muscle
d. Has an oxygen dissociation curve that is linear
10. The following prevents the lung from overfilling during inhalation
a. Carotid chemoreceptors
b. Aortic arch baroreceptors
c. The Herring – Bruer reflex
d. Depletion of surfactant
11. The receptors of the Herring – Bruer reflex are located in
a. Carotid and aortic bodies
b. Arteries of cerebral circulation
c. Lungs
d. Respiratory centre
12. The partial pressure of oxygen in dry air at sea level is
a. 760 mmHg
b. 159 mmHg
c. 149 mmHg
d. 104 mmHg
13. Factors that favor formation of carbamino – hemoglobin include
a. Pressure of carbon monoxide
b. Carbonic anhydrase
c. Increase in oxygen tension
d. Decrease in pH
14. Which of the following statements is true of oxygen unloading
a. Decreases with increase in temperature
b. Increases with increased PCO2
c. Decreases with increase in 2,3 DPG
d. Increases with increase in PO2
15. Concerning the chemical regulation of respiration
a. The central chemoreceptors sense the oxygen tension of arterial blood
b. In humans the peripheral chemoreceptors are located in the carotid sinus and aortic
c. Hydrogen ion concentration is not important
d. Central chemoreceptors detect changes in PCO2
16. Which is NOT a non respiratory function of the lung
a. Speech
b. Resonance of sound
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c. Temperature control
d. Control of blood pH
17. In which type of hypoxia will oxygen therapy be most useful
a. Stagnant hypoxia
b. Anemic hypoxia
c. Histotoxic hypoxia
d. Hypoxic hypoxia
18. A patient has an alveolar PA-O2 of 60 mmHg and a systemic arterial Pa-O2 of 56
mmHg. The most likely explanation of these values is
a. Hypoventilation
b. Diffusion limitation
c. Hypoperfusion
d. Shunting of blood
19. Alveolar surfactant acts to increase pulmonary
a. Surface tension
b. Compliance
c. Airway resistance
d. Blood flow
20. Air is warmed and humidified in
a. Pharynx
b. The nasal cavity
c. The glottis
d. The lungs
21. Breathing in as much air as possible after a normal expiration is termed
a. Tidal volume
b. Inspiratory capacity
c. Inspiratory reserve volume
d. Total lung volume
22. Hypoxia caused by inability of tissues to uptake and utilize oxygen is called
a. Anemic hypoxia
b. Tissue ischemia
c. Hypoxic hypoxia
d. Histotoxic hypoxia
23. Normal resting expiratory breaths are called
a. Tidal volume
b. Expiratory volume
c. Vital capacity
d. Residual volume
24. During a condition in which there is hypoventilation
a. Arterial oxygen levels do not change
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b. Arterial CO2 levels will fall
c. There may be a rise in pH of blood
d. There may be a decrease in bicarbonate level
25. At high altitude, the number of RBCs increases:
a. To trap O2 from the rarefied air at low PO2
b. To adapt with the oxygen deficiency
c. To remove more CO2
d. To increase metabolism
26. The following hormone is secreted in high quantity during mountain ascent:
a. Adrenaline
b. Erythropoietin
c. Thyroxine
d. Aldosterone
27. Which gas mixture is used by divers to prevent oxygen toxicity
a. Oxygen and carbon dioxide
b. Oxygen and nitrogen
c. Oxygen and helium
d. Oxygen, carbon dioxide and nitrogen
28. With regard to dead space
a. Total dead space is same as physiological dead space
b. Total dead space in a healthy individual is zero
c. Blockage of pulmonary capillary flow would increase total dead space
d. Thickening of the blood gas barrier may increase the physiological dead space
29. In the transportation of carbon dioxide
a. 10% is carried as dissolved gas
b. 20% is carried as bicarbonate
c. 70% is carried as carbamino – compound
d. A rise in PO2 facilitates CO2 binding by hemoglobin
30. Hemoglobin
a. Is a protein with a ferric – base (Fe3+) heme component
b. Binds covalently with oxygen
c. Is found only in red blood cells
d. Becomes oxidized upon binding with oxygen
31. Concerning the oxygen – hemoglobin dissociation curve
a. It is linear because the initial binding of oxygen facilitates more binding of oxygen
until all sites are occupied
b. At the tissue level the curve may shift to the right and therefore favor oxygen release
c. Fetal hemoglobin has a lower affinity for oxygen than adult hemoglobin
d. Lower pH causes the curve to shift to the left
32. In decompression sickness, which one of the following is FALSE
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a. Air bubbles form in blood
b. Treatment is by rapid decompression
c. The air bubbles can cause embolism
d. The patients presents with ‘bends’ and ‘chokes’
33. In space the following effects occur on the body EXCEPT
a. There is weightlessness
b. Work capacity increases due to lack of gravity
c. There may be loss of bone density
d. Motion sickness occurs
34. The chloride shift occurring during carbon dioxide transport
a. It occurs in systemic veins
b. Chloride ions move out of the RBC while bicarbonate ions move into the RBC
c. The enzyme carbonic anhydrase catalyzes the exchange
d. Chloride ions are buffered by hemoglobin
Study the diagram below and use it to answer the questions that follow.
35. The following is TRUE from the diagram above
a. Fetal Hb has lower affinity for oxygen than adult Hb
b. Fetal Hb has higher affinity for oxygen than adult Hb
c. Oxygen would dissociate quicker from fetal Hb than from adult Hb
d. When going to a high altitude area having fetal Hb would be a disadvantage
36. ONE of the following factors would cause the adult Hb – O2 dissociation curve to shift in
the direction of the fetal Hb – O2 dissociation curve
a. Low tissue PO2
b. Decrease in blood pH
c. Increase in body temperature
d. Decrease in PCO2
37. The upper respiratory tract consist of the following EXCEPT:
a. The larynx
b. The nasal cavity
c. The paranasal sinuses
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d. The pharynx (throat)
38. The trachea:
a. Is sometimes called the gullet
b. Posterior and lateral walls of the trachea are supported by 15 to 20 C – shaped
tracheal cartilages
c. Is immediately posterior to the esophagus
d. Carina is the most inferior tracheal cartilage that separates the primary bronchi at
their origin
39. The following are the characteristics of pulmonary vessels EXCEPT:
a. The pulmonary artery is thin, with a wall thickness one third that of the aorta
b. The small bronchial arteries that supply the lungs originate from the systemic
circulation and carries oxygenated blood
c. The small bronchial arteries that supply the lungs originate from the pulmonary artery
and carries deoxygenated blood
d. The pulmonary arterial tree has a large compliance due to their thin walls
40. About the three zones of pulmonary circulation, the following statements are true
a. Zone 1: No blood flow during all portions of the cardiac cycle
b. Zone 2: Intermittent blood flow only during the pulmonary arterial pressure peaks
c. Zone 3: Continuous blood flow because the alveolar capillary pressure remains
greater than alveolar air pressure during the entire cardiac cycle
d. Zone 2: There is continuous blood flow at all times
41. The tidal volume in respiration:
a. This is the amount of air that remains in the lungs at the end of normal expiration
b. This is the amount of air a person can breathe in, beginning at the normal expiratory
level and distending the lungs to the maximum amount
c. This is the volume of air inspired or expired with each normal breath
d. This is the extra volume of air that can be inspired with full force
42. The vital capacity in respiration is:
a. The maximum amount of air a person can expel from the lungs after first filling the
lungs to their maximum extend and then expiring to the maximum extent
b. The maximum volume to which the lungs can be expanded with the greatest possible
c. Equals the tidal volume plus the inspiratory reserve volume
d. Equals the inspiratory reserve volume plus the expiratory reserve volume only
43. Surfactant lining the alveoli
a. Helps prevent alveolar collapse
b. Is produced in the alveolar type I cells and secreted into the alveolus
c. Is increased in the lungs of heavy smokers
d. Is a glycolipid complex
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44. The following are causes of hypoxic hypoxia EXCEPT:
a. When low PO2 is inspired in the air by normal individuals in high altitudes or in a
closed space
b. When a person has had sudden hemorrhage loss of blood
c. When a person has pulmonary disease e.g. pneumonia or asthma
d. When there is communication of the right and left side of the heart – shunt
45. Which of the following statements is TRUE about stagnant hypoxia:
a. The atmospheric PO2 is very low hence the person is affected
b. The atmospheric PO2 high but the arterial PO2 is normal in volume and percentage
c. Atmospheric PO2 and arterial PO2 are normal on percentage and volume but due to
slow circulation, the vital organs are affected
d. It is caused by carbon monoxide poisoning
46. After expiration of normal tidal volume, a subject breathes in as much air as possible.
The volume of air inspired is the:
a. Inspiratory reserve volume
b. Vital capacity
c. Inspiratory capacity
d. Functional residual capacity
47. The normal pressure in the intrapleural space is:
a. -10 to -12 mmHg
b. +10 to +12 mmHg
c. -5 mmHg
d. +5 mmHg
48. The method by which majority of the respiratory volumes can be measured is the:
a. Phonograph
b. Resuscitator
c. Spirometer
d. Underwater – seal breathing apparatus
49. The following are true about lung compliance EXCEPT
a. The lung compliance is the extent to which the lungs will expand for each unit
increase in transpulmonary pressure
b. The total compliance of both lungs together in the normal adult human being
averages about 20 milliliter of air per cm of H2O transpulmonary
c. It is the change in lung volume per unit change in airway pressure (∆V/∆P)
d. Compliance depends on lung volume hence a person with one lung has half the ∆V
for a given ∆P
50. During inspiration:
a. The rectus abdominal muscles contract
b. There is relaxation of the diaphragm
c. The internal intercostals muscles contract
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d. The diaphragm contracts
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