NEET UG · Biology

Breathing and Exchange of Gases

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1. A person has a Tidal Volume (TV) of 500 mL, an Inspiratory Reserve Volume (IRV) of 3000 mL, and an Expiratory Reserve Volume (ERV) of 1000 mL. If their Residual Volume (RV) is 1200 mL, what is their Functional Residual Capacity (FRC)? 2. Which of the following forms transports the largest percentage of CO2 in the blood? 3. During CO2 transport, carbonic anhydrase facilitates the formation of carbonic acid inside RBCs. What is the fate of this carbonic acid? 4. Chronic obstructive pulmonary disease (COPD) patients often develop 'blue bloater' symptoms, including cyanosis and edema. The cyanosis is primarily due to: 5. Carbon dioxide is transported in blood primarily as bicarbonate ions. The enzyme catalyzing the reaction of CO2 and water to form carbonic acid in red blood cells is: 6. A scuba diver ascending rapidly from a depth experiences 'the bends'. This condition is primarily due to: 7. Assertion (A): The PO2 of arterial blood is a more potent regulator of respiration than PCO2. Reason (R): Peripheral chemoreceptors are more sensitive to changes in PO2 than central chemoreceptors. 8. Each molecule of hemoglobin can maximally bind to how many molecules of oxygen? 9. The alveolar epithelium primarily consists of: 10. A patient presents with dyspnea, barrel chest appearance, and chronic cough. Spirometry shows a significantly increased Residual Volume (RV) and Total Lung Capacity (TLC), but reduced FEV1/FVC ratio. These findings are most consistent with: 11. A premature infant born with underdeveloped surfactant-producing cells would likely exhibit: 12. The Haldane effect states that the deoxygenation of blood increases its ability to carry carbon dioxide. Which of the following best explains the underlying mechanism? 13. A patient sustains a severe injury resulting in paralysis of the diaphragm. Which of the following would be the most immediate and significant consequence? 14. The fluid in the pleural cavity serves to: 15. The chemosensitive area of the brain is highly sensitive to which of the following blood parameters? 16. Anatomical dead space refers to: 17. The primary site of gaseous exchange in humans is the: 18. The pneumotaxic center, located in the pons, has what effect on respiration? 19. The primary function of epiglottis during swallowing is to: 20. If a person's blood pH decreases significantly, what effect would this have on the oxygen dissociation curve and subsequent oxygen release to tissues? 21. If the atmospheric pressure is 760 mmHg and the percentage of oxygen in the atmosphere is 21%, what is the approximate partial pressure of nitrogen (PN2) in the dry atmospheric air? 22. Which of the following reflexes prevents over-inflation of the lungs? 23. In a patient with metabolic acidosis (e.g., due to uncontrolled diabetes), what compensatory respiratory response would be expected? 24. The nasal cavity plays a crucial role in conditioning inhaled air. Which of the following functions is *not* primarily associated with the nasal cavity? 25. In the blood, a small percentage of oxygen is transported in a dissolved state. What is the approximate percentage? 26. Which of the following statements correctly describes the muscular activity during a forceful expiration? 27. Arrange the following steps of oxygen transport from the alveoli to the tissue cells in the correct sequence: 1. Diffusion of O2 into the blood. 2. Binding of O2 to hemoglobin. 3. Diffusion of O2 into tissue cells. 4. Transport of O2 in arterial blood. 5. Dissociation of O2 from hemoglobin. 28. In a patient suffering from severe asthma, which of the following physiological changes is most likely to be observed? 29. If a person hyperventilates excessively, blowing off large amounts of CO2, what would be the immediate effect on their blood pH? 30. The Bohr effect describes the phenomenon where a decrease in pH (acidosis) or an increase in PCO2 shifts the oxyhemoglobin dissociation curve to the right. What is the physiological advantage of this effect? 31. Which of the following represents the maximum amount of air a person can breathe in after a forceful expiration? 32. Why is the chloride shift important during CO2 transport in red blood cells? 33. A person has a TV of 600 mL, IRV of 2400 mL, ERV of 900 mL, and a Residual Volume (RV) of 1100 mL. What is their Inspiratory Capacity (IC) and Expiratory Capacity (EC) respectively? 34. The primary respiratory rhythm-generating center in the brain is located in the: 35. During inspiration, the diaphragm: 36. The C-shaped cartilaginous rings are present in the wall of the trachea. What is their primary function? 37. Which of the following factors would decrease the rate of diffusion of gases across the alveolar-capillary membrane? 38. A shift of the oxyhemoglobin dissociation curve to the right would be caused by: 1. Increased PCO2 2. Increased pH 3. Increased temperature 4. Increased 2,3-BPG 39. If a person hyperventilates voluntarily (breathes rapidly and deeply), what would be the immediate effect on their blood gas levels and subsequent urge to breathe? 40. Infant respiratory distress syndrome (IRDS) is caused by insufficient production of surfactant. This leads to: 41. Anatomical dead space refers to the volume of air in the conducting airways that does not participate in gas exchange. Which of the following statements about physiological dead space is TRUE? 42. The respiratory membrane, across which gas exchange occurs, consists of all of the following EXCEPT: 43. During strenuous exercise, local tissue PO2 decreases, and PCO2 increases. How does this affect oxygen delivery to the active muscles? 44. The rhythmicity center for respiration, responsible for generating the basic respiratory rhythm, is located in the: 45. The Haldane effect states that the binding of oxygen to hemoglobin facilitates the unloading of CO2 from the blood. This occurs because: 46. The presence of surfactant in the alveoli is critical because it: 47. Which of the following muscle groups is primarily responsible for expanding the thoracic cavity vertically during quiet inspiration? 48. Which of the following statements correctly describes the partial pressures of gases in normal arterial blood (systemic arteries)? 49. The fluid present in the pleural cavity serves to: 50. Each hemoglobin molecule can maximally bind with how many oxygen molecules?