Test Bank for Neonatal and Pediatric Respiratory
Care, 6th Edition
by Brian K. Walsh
,Chapter 1: Fetal Lung Developme
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ntTest Bank
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MULTIPLE CHOICE VG
1. Which of the following phases of human lung development is characterized by the form
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ationof a capillary network around airway passages?
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a. Pseudoglandular
b. Saccular
c. Alveolar
d. Canalicular
ANS: D VG
The canalicular phase follows the pseudoglandular phase, lasting from approximately 17
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weeks to 26 weeks of gestation. This phase is so named because of the appearance of vas
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cularchannels, or capillaries, which begin to grow by forming a capillary network around
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the air passages. During the pseudoglandular stage, which begins at day 52 and extends
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to week 16 of gestation, the airway system subdivides extensively and the conducting ai
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rway system develops, ending with the terminal bronchioles. The saccular stage of devel
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opment, which takes place from weeks 29 to 36 of gestation, is characterized by the deve
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lopment of sacs thatlater become alveoli. During the saccular phase, a tremendous increa
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se in the potential
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gas-
exchanging surface area occurs. The distinction between the saccular stage and the al
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veolar stage is arbitrary. The alveolar stage stretches from 39 weeks of gestation to t
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erm.This stage is represented by the establishment of alveoli.
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REF: pp. V G VGVGV G 3-5
2. Regarding postnatal lung growth, by approximately what age do most of the alveoli th
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at willbe present in the lungs for life develop?
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a. 6 months VG
b. 1 year VG
c. 1.5 years VG
d. 2 years VG
ANS: C VG
Most of the postnatal formation of alveoli in the infant occurs over the first 1.5 years o
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f life. At 2 years of age, the number of alveoli varies substantially among individuals. Af
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ter 2 yearsof age, males have more alveoli than do females. After alveolar multiplication
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Gends, the alveoli continue to increase in size until thoracic growth is completed.
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REF: p. 6 VG VG
3. The respiratory therapist is evaluating a newborn with mild respiratory distress due to t
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rachealstenosis. During which period of lung development did this problem develop?
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a. Embryonal
b. Saccular
c. Canalicular
d. Alveolar
ANS: A VG
, The initial structures of the pulmonary tree develop during the embryonal stage. Error
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s in development during this time may result in laryngeal, tracheal, or esophageal atres
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ia or stenosis. Pulmonary hypoplasia, an incomplete development of the lungs characteri
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zed by anabnormally low number and/or size of bronchopulmonary segments and/or al
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veoli, can develop during the pseudoglandular phase. If the fetus is born during the can
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alicular phase (i.e., prematurely), severe respiratory distress can be expected because the
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inadequately developed airways, along with insufficient and immature surfactant produ
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ction by alveolar type II cells, gives rise to the constellation of problems known as infa
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nt respiratory distress syndrome.
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REF: VGVGVG p. 6 VG
4. Which of the following mechanisms is (are) responsible for the possible association betw
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eenoligohydramnios and lung hypoplasia?
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I. Abnormal carbohydrate metabolism VG VG
II. Mechanical restriction of the chest wall VG VG VG VG VG
III. Interference with fetal breathing VG VG VG
IV. Failure to produce fetal lung liquid VG VG VG VG VG
a. I and III only VG VG VG
b. II and III only VG VG VG
c. I, II, and IV only VG VG VG VG
d. II, III, and IV only VG VG VG VG
ANS: D VG
Oligohydramnios, a reduced quantity of amniotic fluid present for an extended period of ti
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me,
with or without renal anomTaE
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, iB
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iaE
teLdLwEitR
h lu
. CnO
gMhypoplasia. The mechanisms by
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which amniotic fluid volume influences lung growth remain unclear. Possible explanatio
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ns for VG
reduced quantity of amniotic fluid include mechanical restriction of the chest wall, inter
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ference with fetal breathing, or failure to produce fetal lung liquid. These clinical and e
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xperimental observations possibly point to a common denominator, lung stretch, as bei
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ng amajor growth stimulant.
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REF: pp. 6-7 VG VG
5. What is the purpose of the substance secreted by the type II pneumocyte?
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a. To increase the gas exchange surface area
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b. To reduce surface tension VG VG VG
c. To maintain lung elasticityVG VG VG
d. To preserve the volume of the amniotic fluid
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ANS: B VG
The primary role of mammalian surfactant is to lower the surface tension within the alv
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eolus, specifically at the air–
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liquid interface. This allows the delicate structure of the alveolus to expand when filled
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with air. Without surfactant, the alveolus remains collapsed because of thehigh surface te
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nsion of the moist alveolar surface. Surfactant is composed predominantly of an intricate
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Gblend of phospholipids, neutral lipids, and proteins.
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REF: p. 8 VG VG
, 6. Which of the following tests of the amniotic fluid have been shown to be sensitive indic
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atorsof lung maturity?
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a. Levels of prednisone VG VG
b. Levels of epidermal growth factor VG VG VG VG
c. Levels of prostaglandins VG VG
d. Levels of phosphatidylglycerol and phosphatidylcholine
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ANS: D VG
Of clinical relevance during late gestation, analysis of amniotic fluid for the concentratio
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n ofphosphatidylglycerol and phosphatidylcholine has been shown to be a sensitive indi
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cator of the state of fetal lung maturity.
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REF: p. 8 VG VG
7. Approximately how much fetal lung fluid is secreted daily?
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a. About 150 to 200 ml
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b. About 250 to 300 ml
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c. About 350 to 400 ml
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d. About 450 to 500 ml
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ANS: B VG
Fetal lungs are secretory organs that make breathing-
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like movements but serve no respiratory function before birth. They secrete
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about 250 to 300 ml of liquid per day.
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8. The lung bud emerges from which of the following structures?
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a. The pharynx
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b. The foregut
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c. The mesenchyme
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d. The tubular epithelium
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ANS: A VG
The embryonal phase includes primitive lung development and is generally regarded to encompass the first
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2 months of gestation.
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The lung begins to emerge as a bud from the pharynx 26 days after conception.
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