pulmonary physiology questions

B. Posterior cricoarytenoid

1. Which muscle is the sole abductor of the larynx involved in respiration?

A. Sternocleidomastoid
B. Posterior cricoarytenoid
C. External intercostal
D. Scalene

B. Vital Capacity

2. Which of the following lung volumes includes IRV, TV, and ERV?

A. Functional Residual Capacity
B. Vital Capacity
C. Inspiratory Capacity
D. Total Lung Capacity

B. Stretch of alveolar epithelium

3. What stimulates surfactant production in alveolar type II cells?

A. Hypoxia
B. Stretch of alveolar epithelium
C. Decrease in CO₂ levels
D. Neural stimulation

C. Increased CO₂

4. Which condition is most likely to cause a rightward shift in the oxyhemoglobin dissociation curve?

A. Decreased temperature
B. Alkalosis
C. Increased CO₂
D. Fetal hemoglobin

C. Inversely proportional to tissue thickness

5. What does Fick’s law state about gas diffusion?

A. Proportional to tissue thickness
B. Unrelated to gas pressure
C. Inversely proportional to tissue thickness
D. Unrelated to surface area

C. . Central and peripheral chemoreceptors

6. What controls the ventilatory response to increased arterial CO₂?

A. Only peripheral chemoreceptors
B. Sympathetic stimulation
C. Central and peripheral chemoreceptors
D. Pulmonary baroreceptors

B. Trachea and bronchi

7. Which of the following represents dead space ventilation?

A. Alveolar regions with perfusion
B. Trachea and bronchi
C. Alveoli undergoing gas exchange
D. Capillary volume

C. Upper extrathoracic airway

8. What is the most significant site of airway resistance under normal conditions?

A. Alveolar ducts
B. Terminal bronchioles
C. Upper extrathoracic airway
D. Capillaries

D. J-receptors

9. What type of receptor is responsible for rapid shallow breathing in pulmonary edema?

A. Baroreceptors
B. Stretch receptors
C. Irritant receptors
D. J-receptors

D. Residual volume

10. Which volume remains in the lungs after maximal expiration?

A. Inspiratory reserve volume
B. Tidal volume
C. Vital capacity
D. Residual volume

C. Reduce surface tension

11. What is the role of surfactant in the lungs?

A. Increase airway resistance
B. Prevent CO₂ buildup
C. Reduce surface tension
D. Stimulate cough

C. Phrenic

12. Which nerve innervates the diaphragm?

A. Vagus
B. Hypoglossal
C. Phrenic
D. Intercostal

A. Inspiratory capacity

13. Which lung volume is the sum of tidal volume and inspiratory reserve volume?

A. Inspiratory capacity
B. Vital capacity
C. Total lung capacity
D. Functional residual capacity

B. O₂ is unloaded more easily at the tissues

14. What does a right shift of the oxyhemoglobin dissociation curve indicate?

A. Hemoglobin holds O₂ more tightly
B. O₂ is unloaded more easily at the tissues
C. Less O₂ available for diffusion
D. Increased hemoglobin concentration

C. Irritant stimulation of vagal afferents

15. What mechanism initiates cough reflex?

A. CO₂ accumulation
B. Alveolar distension
C. Irritant stimulation of vagal afferents
D. Epiglottis pressure

B. Becomes more negative

16. What happens to pleural pressure during inspiration?

A. Becomes more positive
B. Becomes more negative
C. Remains the same
D. Fluctuates randomly

B. Abdominals and internal intercostals

17. Which muscles are activated during forced expiration?

A. External intercostals and diaphragm
B. Abdominals and internal intercostals
C. Diaphragm and SCM
D. Trapezius and scalenes

B. Radius of airway

18. What determines airway resistance according to Poiseuille’s law?

A. Surface tension
B. Radius of airway
C. Oxygen pressure
D. Tidal volume

B. ERV + RV

19. What is functional residual capacity?

A. Air after full inhalation
B. ERV + RV
C. IRV + TV
D. VC + RV

A. Stretch receptor

20. Which receptor inhibits inspiration via vagal afferents?

A. Stretch receptor
B. J-receptor
C. Chemoreceptor
D. Golgi tendon organ

B. Binds and transports O2

21. What is the role of hemoglobin in O₂ transport?

A. Reduces O₂ delivery
B. Binds and transports O₂
C. Releases CO₂
D. Stimulates chemoreceptors

C. Decreased temperature

22. What condition would shift the oxyhemoglobin curve left?

A. Fever
B. Acidosis
C. Decreased temperature
D. Increased CO₂

C. Minute ventilation

23. What is the product of tidal volume and respiratory rate?

A. Vital capacity
B. Alveolar ventilation
C. Minute ventilation
D. Inspiratory capacity

C. PCO₂ increases

24. What happens during alveolar hypoventilation?

A. PCO₂ decreases
B. PO₂ increases
C. PCO₂ increases
D. Airway resistance decreases

B. Upper airway abductor muscle activity

25. What helps maintain airway patency during negative pressure breathing?

A. Expiratory muscle contraction
B. Upper airway abductor muscle activity
C. Surfactant inhibition
D. Pulmonary baroreceptors

C. It increases

26. What happens to alveolar PO₂ during inspiration?

A. It decreases
B. It stays the same
C. It increases
D. It matches venous PO₂

C. Alveolar ventilation

27. What is the primary determinant of alveolar PCO₂?

A. Lung compliance
B. Surface tension
C. Alveolar ventilation
D. Diaphragm strength

C. Residual volume

28. Which lung volume cannot be measured by spirometry?

A. Tidal volume
B. Inspiratory reserve volume
C. Residual volume
D. Vital capacity

B. Volume of air reaching alveoli per minute

29. What best describes alveolar ventilation?

A. Dead space × breathing frequency
B. Volume of air reaching alveoli per minute
C. Air remaining in conducting zone
D. Maximal inspiratory effort

C. Less efficient ventilation

30. What occurs with increased dead-space ventilation?

A. Improved gas exchange
B. Decreased oxygen demand
C. Less efficient ventilation
D. Reduced work of breathing

C. Decreases

31. What happens to lung compliance in pulmonary fibrosis?

A. Increases
B. Remains unchanged
C. Decreases
D. Only increases during exercise

C. Hyperventilation

32. What type of ventilation increases PaO₂ and decreases PaCO₂?

A. Hypoventilation
B. Shallow breathing
C. Hyperventilation
D. Dead-space ventilation

C. Maintain alveolar patency

33. What is the purpose of periodic sighs during breathing?

A. Reduce lung compliance
B. Increase airway resistance
C. Maintain alveolar patency
D. Stimulate J-receptors

D. 90–100 mm Hg

34. What is a normal PO₂ value in arterial blood?

A. 20 mm Hg
B. 40 mm Hg
C. 60 mm Hg
D. 90–100 mm Hg

B. Medullary respiratory centers

35. What structure is responsible for generating inspiratory rhythm?

A. Carotid body
B. Medullary respiratory centers
C. Spinal interneurons
D. Aortic baroreceptors

B. Enhances it via chemoreceptors

36. What does a decrease in blood pH do to ventilation?

A. Suppresses it
B. Enhances it via chemoreceptors
C. Causes breath-holding
D. No effect

B. Aortic arch and carotid bodies

37. Where are peripheral chemoreceptors located?

A. In alveolar walls
B. Aortic arch and carotid bodies
C. Cerebral cortex
D. Lung hilum

C. Decreases

38. What happens to hemoglobin's affinity for oxygen in active muscle?

A. Increases
B. Stays the same
C. Decreases
D. Depends on hemoglobin type

C. Carbonic anhydrase

39. What enzyme catalyzes the conversion of CO₂ to carbonic acid in red blood cells?

A. Lactate dehydrogenase
B. ATP synthase
C. Carbonic anhydrase
D. Hemoglobinase

C. 500 mL

40. What is the average tidal volume for a healthy adult?

A. 100 mL
B. 250 mL
C. 500 mL
D. 1,000 mL

C. Upper extrathoracic airway

41. What causes the greatest airflow resistance in a healthy person?

A. Terminal bronchioles
B. Alveolar sacs
C. Upper extrathoracic airway
D. Pulmonary veins

B. Increases it proportionally to metabolic rate

42. How does exercise affect ventilation initially?

A. Slows it
B. Increases it proportionally to metabolic rate
C. Reduces tidal volume
D. Decreases CO₂ output

C. Greater in the bases

43. What effect does gravity have on pulmonary blood flow in an upright person?

A. Equal throughout the lung
B. Greater in the apices
C. Greater in the bases
D. No effect

D. Shunt-like condition

44. What effect does a V/Q ratio near 0 (zero) indicate?

A. Normal gas exchange
B. No perfusion
C. No ventilation
D. Shunt-like condition

C. 60 mm Hg

45. What is the PO₂ at which hemoglobin saturation begins to drop rapidly?

A. 100 mm Hg
B. 80 mm Hg
C. 60 mm Hg
D. 40 mm Hg

C. Bicarbonate ion

46. What is the most common form of CO₂ transport in the blood?

A. Dissolved gas
B. Carbaminohemoglobin
C. Bicarbonate ion
D. CO₂ bound to albumin

A. Alveoli

47. What part of the respiratory system has the highest compliance?

A. Alveoli
B. Bronchi
C. Rib cage
D. Diaphragm

B. Increased alveolar PO₂

48. Which of the following increases the oxygen diffusion gradient in the lung?

A. Increased hemoglobin
B. Increased alveolar PO₂
C. Low pH
D. Pulmonary edema

B. Decreased mechanical advantage

49. What effect does flattening of the diaphragm have in COPD?

A. Increased inspiratory strength
B. Decreased mechanical advantage
C. Increased venous return
D. Improved cough efficiency

C. Hyperventilation

50. What happens when alveolar ventilation is greater than metabolic demand?

A. Hypoventilation
B. Respiratory acidosis
C. Hyperventilation
D. Alveolar collapse