EGANS LATEST TEST BANK

1. By what mechanism does gas exchange across the lung occur? a. active transport b. facilitated diffusion c. facilitated transport d. simple diffusion ANS: D This close “match” of gas and blood across a large but extremely thin blood-gas barrier membrane enables efficient gas exchange to occur by simple diffusion. DIF: Application REF: p. 148 OBJ: 1 2. What is the primary purpose of the respiratory system? a. continuous absorption of oxygen and excretion of carbon dioxide b. filtering to prevent allergens and microbesfrom reaching the lungs c. transport oxygenated blood to the tissues d. warm and humidify inspired gas ANS: A The respiratory system's primary function is the continuous absorption of oxygen and the excretion of carbon dioxide. DIF: Application REF: p. 148 OBJ: 1 3. What is meant by “internal respiration”? a. any gas exchange that occurs inside the body b. consumption of oxygen in the mitochondria c. continuous absorption of oxygen and excretion of carbon dioxide d. exchange of gases between the blood and the tissue ANS: D This process supports internal respiration, which is the exchange of gases between blood and tissues. DIF: Application REF: p. 148 OBJ: 1 4. Developmental morphogenesis of the human respiratory system can be categorized into: a. three periods b. five stages c. 6 weeks d. 40 weeks ANS: B Figure 8-1 shows the various stages of lung development, and Table 8-1 summarizes the major developmental events in each phase. DIF: Application REF: p. 149 OBJ: 1 5. The human genome contains pairs of chromosomes. a. 16 b. 23 c. 46 d. 50 ANS: B DNA is organized into 23 pairs ofsupercoiled masses that are called chromosomes. DIF: Recall REF: p. 150 OBJ: 2 6. Which chromosome has been found to carry the defective gene responsible for the development of cystic fibrosis? a. 1 b. 7 c. 15 d. 23 ANS: B The defective gene that is responsible for defective CFTR is located on chromosome 7 in the q31.2 region and has been found to be mutable in more than 1500 different ways. DIF: Recall REF: p. 191 OBJ: 2 7. The fetus is potentially viable if born prematurely after how many weeks of gestation? a. 12 to 16 weeks b. 18 to 20 weeks c. 24 to 26 weeks d. 28 to 32 weeks ANS: C At the end of the canalicular period (24 to 26 weeks of gestation), the fetus, if born, is capable ofsufficient gas exchange and is viable ifsupported completely with an artificial airway, oxygen, ventilatory support, and surfactant administration. DIF: Application REF: p. 149 OBJ: 1 8. The fetus is potentially viable if born at the end of which stage of development? a. alveolar b. canalicular c. pseudoglandular d. saccular ANS: B At the end of the canalicular period (24 to 26 weeks of gestation), the fetus, if born, is capable ofsufficient gas exchange and is viable ifsupported completely with an artificial airway, oxygen, ventilatory support, and surfactant administration. DIF: Application REF: p. 149 OBJ: 1 9. During which phase of fetal development do mature alveoli appear? a. alveolar b. canalicular c. pseudoglandular d. saccular ANS: A The development of mature alveoli, accompanied by capillary proliferation within the walls, marks the final phase of lung development and is known as the alveolar period. DIF: Application REF: p. 149 OBJ: 1 10. Which of the following is an index commonly used to determine relative lung maturity? a. FRC/TLC ratio b. L:S ratio c. RQ ratio d. SP-A ANS: B Quantification of these phospholipids (the L:S ratio and PG concentration) provides a predictive index of the lung maturity in the fetus before birth and the risks of developing respiratory disease. DIF: Application REF: p. 153 OBJ: