NEET UG - Breathing and exchange of gases - mechanism of respiration, transport of gases Online Test (MCQ Quiz)

1. What is the primary site of gas exchange in the human respiratory system?

A) Trachea B) Bronchioles C) Alveoli D) Larynx

2. The process of breathing is also known as:

A) Respiration B) Ventilation C) Inspiration D) Exhalation

3. During inspiration, the diaphragm:

A) Relaxes and flattens B) Contracts and flattens C) Relaxes and becomes dome-shaped D) Contracts and becomes dome-shaped

4. Which muscles are involved in forced exhalation?

A) External intercostal muscles B) Diaphragm C) Internal intercostal muscles and abdominal muscles D) Serratus anterior

5. The pressure within the pleural cavity is known as:

A) Intrapulmonary pressure B) Intrapleural pressure C) Atmospheric pressure D) Alveolar pressure

6. What happens to the volume of the thoracic cavity during inspiration?

A) Decreases B) Increases C) Remains unchanged D) Slightly decreases

7. Which law states that the pressure of a gas is inversely proportional to its volume at a constant temperature?

A) Dalton's Law B) Henry's Law C) Boyle's Law D) Charles's Law

8. The partial pressure of oxygen in the alveoli is approximately:

A) 40 mmHg B) 45 mmHg C) 104 mmHg D) 159 mmHg

9. Carbon dioxide diffuses from the blood into the alveoli because:

A) Its partial pressure is higher in the alveoli B) Its partial pressure is lower in the alveoli C) Its partial pressure is higher in the blood D) Its partial pressure is lower in the blood

10. What is the approximate partial pressure of carbon dioxide in the deoxygenated blood entering the lungs?

A) 40 mmHg B) 45 mmHg C) 95 mmHg D) 104 mmHg

11. The solubility of oxygen in blood plasma is:

A) Very high B) Moderate C) Very low D) Negligible

12. Approximately what percentage of oxygen is transported by hemoglobin in the blood?

A) 3% B) 7% C) 20% D) 97%

13. Oxygen binds to which part of the hemoglobin molecule?

A) Globin chains B) Heme group C) Iron atom D) Amino acids

14. The binding of oxygen to hemoglobin is a reversible process influenced by:

A) pH and temperature B) Partial pressure of O2 C) Partial pressure of CO2 D) All of the above

15. An increase in partial pressure of carbon dioxide in the blood leads to:

A) Decreased affinity of hemoglobin for oxygen B) Increased affinity of hemoglobin for oxygen C) No change in hemoglobin affinity D) Dissociation of oxygen from hemoglobin

16. The Bohr effect describes the:

A) Transport of CO2 by hemoglobin B) Binding of oxygen to hemoglobin C) Effect of pH and CO2 on oxygen dissociation curve D) Mechanism of breathing

17. At the tissues, oxygen is released from hemoglobin due to:

A) Higher partial pressure of oxygen B) Lower partial pressure of carbon dioxide C) Lower partial pressure of oxygen and higher partial pressure of CO2 D) Higher pH

18. Which form is the majority of carbon dioxide transported in the blood?

A) Dissolved in plasma B) Bound to hemoglobin C) As bicarbonate ions D) Bound to plasma proteins

19. The enzyme that catalyzes the formation of carbonic acid from CO2 and H2O in red blood cells is:

A) Carbonic anhydrase B) Hemoglobinase C) Carboxypeptidase D) Anhydrase

20. Carbon dioxide is transported from tissues to lungs primarily as:

A) Carbaminohemoglobin B) Dissolved CO2 C) Bicarbonate ions D) Carbonylhemoglobin

21. What is the chloride shift?

A) Movement of chloride ions into red blood cells B) Movement of chloride ions out of red blood cells C) Movement of bicarbonate ions into red blood cells D) Movement of bicarbonate ions out of red blood cells

22. The pCO2 in the tissues is higher than in the blood, facilitating:

A) Oxygen diffusion into tissues B) Carbon dioxide diffusion into blood C) Oxygen diffusion into blood D) Carbon dioxide diffusion out of blood

23. The respiratory center is located in the:

A) Cerebrum B) Cerebellum C) Medulla oblongata and pons D) Spinal cord

24. Which part of the respiratory center primarily controls the rate of breathing?

A) Dorsal respiratory group (DRG) B) Ventral respiratory group (VRG) C) Pontine respiratory group (PRG) D) Pneumotaxic center

25. The pneumotaxic center of the brainstem:

A) Inhibits inspiration B) Stimulates inspiration C) Controls forced exhalation D) Regulates gas exchange

26. Chemoreceptors sensitive to changes in blood pH and CO2 levels are located in the:

A) Lungs and diaphragm B) Medulla oblongata and aortic arch/carotid arteries C) Kidneys and liver D) Brainstem only

27. A decrease in blood pH typically leads to:

A) Decreased breathing rate B) Increased breathing rate C) No change in breathing rate D) Apnea

28. The oxygen-hemoglobin dissociation curve shifts to the right when:

A) pH increases B) Temperature decreases C) pCO2 decreases D) pCO2 increases

29. What is the role of surfactant in the alveoli?

A) To increase surface tension B) To decrease surface tension and prevent alveolar collapse C) To facilitate oxygen diffusion D) To transport carbon dioxide

30. The volume of air remaining in the lungs even after a forceful exhalation is called:

A) Tidal volume B) Inspiratory reserve volume C) Expiratory reserve volume D) Residual volume

31. The amount of air that can be forcibly exhaled after a normal expiration is known as:

A) Inspiratory capacity B) Functional residual capacity C) Expiratory reserve volume D) Vital capacity

32. The total volume of air a person can inhale after a normal exhalation is:

A) Tidal volume B) Inspiratory reserve volume C) Expiratory reserve volume D) Residual volume

33. Vital capacity is the sum of:

A) Tidal volume + Inspiratory reserve volume B) Tidal volume + Expiratory reserve volume C) Inspiratory reserve volume + Expiratory reserve volume D) Tidal volume + Inspiratory reserve volume + Expiratory reserve volume

34. The exchange of gases between blood and tissues occurs at the:

A) Alveolar-capillary membrane B) Pulmonary capillaries C) Systemic capillaries D) Bronchioles

35. The partial pressure of oxygen in the tissues is typically around:

A) 95 mmHg B) 40 mmHg C) 45 mmHg D) 104 mmHg

36. The partial pressure of carbon dioxide in the tissues is typically around:

A) 95 mmHg B) 40 mmHg C) 45 mmHg D) 104 mmHg

37. During expiration, the pressure inside the lungs (intrapulmonary pressure) is:

A) Lower than atmospheric pressure B) Higher than atmospheric pressure C) Equal to atmospheric pressure D) Variable

38. The volume of air breathed in or out during normal quiet breathing is called:

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

39. The primary function of the conducting zone of the respiratory system is:

A) Gas exchange B) Warming, humidifying, and filtering air C) Sound production D) Smell detection

40. The respiratory membrane consists of the alveolar epithelium, capillary endothelium, and their fused basement membrane, facilitating:

A) Blood flow regulation B) Airway clearance C) Efficient gas exchange D) Immune defense

41. When CO2 levels in the blood increase, the pH:

A) Increases B) Decreases C) Remains unchanged D) Fluctuates

42. In the lungs, carbonic anhydrase catalyzes the conversion of bicarbonate ions and H+ back into:

A) Carbon dioxide and water B) Oxygen and water C) Carbonic acid D) Bicarbonate and hydrogen

43. The transport of oxygen by hemoglobin is primarily affected by the partial pressure of:

A) Carbon dioxide B) Nitrogen C) Oxygen D) Water vapor

44. The Bohr effect facilitates the unloading of oxygen at the tissues because:

A) Low pCO2 and high pH in tissues increase hemoglobin's affinity for O2 B) High pCO2 and low pH in tissues decrease hemoglobin's affinity for O2 C) High pCO2 and high pH in tissues increase hemoglobin's affinity for O2 D) Low pCO2 and low pH in tissues decrease hemoglobin's affinity for O2

45. During quiet inspiration, the volume of the thoracic cavity increases primarily due to the contraction of the:

A) Internal intercostal muscles and abdominal muscles B) Diaphragm and external intercostal muscles C) Diaphragm only D) External intercostal muscles only

46. The Hill equation is used to describe the relationship between:

A) Gas pressure and volume B) Oxygen partial pressure and hemoglobin saturation C) Carbon dioxide transport D) Breathing rate and depth

47. The Haldane effect describes the influence of oxygen saturation of hemoglobin on the transport of:

A) Oxygen B) Carbon dioxide C) Nitrogen D) Carbon monoxide

48. At high altitudes, the partial pressure of oxygen is lower, leading to:

A) Increased hemoglobin's affinity for oxygen B) Decreased hemoglobin's affinity for oxygen C) A shift of the oxygen-hemoglobin dissociation curve to the left D) A shift of the oxygen-hemoglobin dissociation curve to the right

49. The central chemoreceptors are most sensitive to changes in:

A) Oxygen levels in the blood B) Carbon dioxide levels in the cerebrospinal fluid C) Nitrogen levels in the blood D) Temperature of the blood

50. The transport of oxygen from the alveoli to the capillaries is driven by a difference in:

A) Partial pressure of CO2 B) Partial pressure of O2 C) Blood pH D) Temperature

Breathing and exchange of gases - mechanism of respiration, transport of gases - Online Test

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