Neonatal and Pediatric
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Respiratory Care 5th Edition
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Walsh Test Bank A+
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, Chapter 1: Fetal Lung Development Test Bank n n n n n n
MULTIPLE CHOICE n
1. Which of the following phases of human lung development is characterized by the
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formation of a capillary network around airway passages?
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a. Pseudoglandular
b. Saccular
c. Alveolar
d. Canalicular
ANS: D n
The canalicular phase follows the pseudoglandular phase, lasting from approximately 17 weeks
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to 26 weeks of gestation. This phase is so named because of the appearance of vascular
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channels,or capillaries, which begin to grow by forming a capillary network around the air
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passages.
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During the pseudoglandular stage, which begins at day 52 and extends to week 16 of gestation,
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the airway system subdivides extensively and the conducting airway system develops, ending
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with the terminal bronchioles. The saccular stage of development, which takes place from
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weeks29 to 36 of gestation, is characterized by the development of sacs that later become
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alveoli.
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During the saccular phase, a tremendous increase in the potential gas- exchanging surface area
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occurs. The distinction between the saccular stage and the alveolar stage is arbitrary. The
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alveolar stage stretches from 39 weeks of gestation to term. This stage is represented by the
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establishment of alveoli.
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REF: pp. 3-5 n n
2. Regarding postnatal lung growth, by approximately what age do most of the alveoli that
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will be present in the lungs for life develop?
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a. 6 months
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,b. 1 year
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c. 1.5 years
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d. 2 years
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ANS: C n
Most of the postnatal formation of alveoli in the infant occurs over the first 1.5 years of life. At 2
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years of age, the number of alveoli varies substantially among individuals. After 2 years of age,
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males have more alveoli than do females. After alveolar multiplication ends, the alveoli
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continueto increase in size until thoracic growth is completed.
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REF: p. 6n n
3. The respiratory therapist is evaluating a newborn with mild respiratory distress due to
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tracheal stenosis. During which period of lung development did this problem develop?
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a. Embryonal
b. Saccular
c. Canalicular
d. Alveolar
ANS: A n
The initial structures of the pulmonary tree develop during the embryonal stage. Errors in
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development during this time may result in laryngeal, tracheal, or esophageal atresia or stenosis.
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Pulmonary hypoplasia, an incomplete development of the lungs characterized by an abnormally
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low number and/or size of bronchopulmonary segments and/or alveoli, can develop during the
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pseudoglandular phase. If the fetus is born during the canalicular phase (i.e., prematurely),
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severerespiratory distress can be expected because the inadequately developed airways, along
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with insufficient and immature surfactant production by alveolar type II cells, gives rise to the
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constellation of problems known as infant respiratory distress syndrome.
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, REF: p. 6 n n
4. Which of the following mechanisms is (are) responsible for the possible association
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between oligohydramnios and lung hypoplasia?
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I. Abnormal carbohydrate metabolism n n
II. Mechanical restriction of the chest wall n n n n n
III. Interference with fetal breathing n n n
IV. Failure to produce fetal lung liquid
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a. I and III only
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b. II and III only
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c. I, II, and IV only
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d. II, III, and IV only
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ANS: D n
Oligohydramnios, a reduced quantity of amniotic fluid present for an extended period of time,
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with or without renal anomalies, is associated with lung hypoplasia. The mechanisms by which
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amniotic fluid volume influences lung growth remain unclear. Possible explanations for
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reducedquantity of amniotic fluid include mechanical restriction of the chest wall, interference
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with fetalbreathing, or failure to produce fetal lung liquid. These clinical and experimental
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observations possibly point to a common denominator, lung stretch, as being a major growth
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stimulant.
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REF: pp. 6-7
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5. What is the purpose of the substance secreted by the type II pneumocyte?
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