Question

8. Which of the following statements about surfactants in the lungs is false? a. Lung surfactant is a detergent-like substance. b. Surfactants increase the cohesive forces between water molecules. c. Certain cells in the alveoli produce surfactants. d. Surface tension influences the amount of effort required to inflate the lungs. e. Premature infants suffer respiratory distress syndrome if natural surfactants are not present within the lungs.

9. Which of the following statements about the mechanics of ventilation in humans is false? a. If the pleural cavity is punctured, the lung may collapse. b. As the diaphragm relaxes, air is expelled from the respiratory system. c. As the diaphragm relaxes, pressure within the pleural cavities increases. d. Less energy is expended during the exhalation phase than during the inhalation phase. e. There is a slight positive pressure within the pleural cavities between breaths.

10. In which of the following PO2 environments would hemoglobin release its O2 most easily? a. 30 mm Hg b. 50 mm Hg c. 70 mm Hg d. 90 mm Hg e. 110 mm Hg

11. In acidic tissues, hemoglobin releases _______ it does in less acidic environments. a. more O2 than b. less O2 than c. more CO2 than d. less CO2 than e. the same amount of O2 and CO2 as

Answer 1

8.The correct answer is :b.Surfactants increase the cohesive forces between water molecules.

Reason: Surfactants do not increase the attraction between the water molecules.

9.The correct answer is:e. There is a slight positive pressure within the pleural cavities between breaths.

Reason:The above statement is false and rest are all true.

10.The correct answer is:a.30 mm Hg

Reason: At 30mm Hg, there is more acidic environment with high CO2,so Hb releases more oxygen.

11.The correct answer is:a.more O₂ than

Reason: In acidic tissues with more CO2,the pH decreases as a result of which the affinity of Hb for oxygen decreases and oxygen releases form bound Hb.