RespiratoryCare5thEdition
k
WalshTestBankA+
k
, Chapter1:FetalLungDevelopmentTestBank t
MULTIPLE CHOICE k
1. Whichofthefollowingphasesofhumanlungdevelopmentischaracterized bythe t t t t t t k
formation of a capillary network around airway passages?
k k k k k k k k
a. Pseudoglandular
b. Saccular
c. Alveolar
d. Canalicular
ANS: D k
Thecanalicularphasefollowsthepseudoglandular phase,lastingfromapproximately 17weeks to
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26 weeks of gestation. This phase is so named because of the appearance ofvascular channels,or
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capillaries, which begin to grow by forming a capillary networkaround the air passages.
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During the pseudoglandular stage, which begins at day 52 and extends to week 16 of
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gestation, the airway system subdivides extensively and the conducting airway system
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develops, ending with the terminal bronchioles. The saccular stage of development, which takes
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place from weeks29 to 36 of gestation, is characterized by the development of sacs that later
k k k k k k k k k k k k k k k k
become alveoli.
k k
Duringthesaccularphase,atremendousincrease inthepotentialgas-exchangingsurfacearea occurs. t k k
The distinction between the saccular stage and the alveolar stage isarbitrary. The alveolar
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stage stretches from 39 weeks of gestation to term. This stage isrepresented by the
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establishment of alveoli.
k k k
REF: pp. 3-5 k k
2. Regardingpostnatal lunggrowth,byapproximatelywhatagedomostofthealveolithat t k t t t
will be present in the lungs for life develop?
k k k k k k k k k
a. 6 monthsk
,b. 1 year k
c. 1.5 years k
d. 2 years k
ANS: C k
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 2years of age,
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males have more alveoli than do females. After alveolarmultiplication ends,the alveoli
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continueto increase in size until thoracic growth iscompleted.
k k k k k k k k
REF: p. 6 k k
3. Therespiratorytherapistisevaluatinganewbornwithmildrespiratorydistressdueto
t t t t
trachealstenosis.Duringwhichperiodoflungdevelopmentdidthisproblemdevelop?
k t t t t
a. Embryonal
b. Saccular
c. Canalicular
d. Alveolar
ANS: A k
The initial structures of the pulmonary tree develop during the embryonal stage.
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Errorsindevelopment duringthis timemay result inlaryngeal, tracheal, or esophageal
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atresiaorstenosis. Pulmonary hypoplasia, an incomplete development of the lungs
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characterizedbyan abnormally low number and/or size of bronchopulmonary segments and/or
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alveoli,candevelop during the pseudoglandular phase. If the fetus is born during
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thecanalicularphase (i.e., prematurely), severerespiratory distress can be expected because
k k k k k k k k k
theinadequately developed airways, along with insufficient and immature
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surfactantproduction by alveolar type II cells, gives rise to the constellation of
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problems knownasinfant respiratory distress syndrome.
k k t k k k
, REF: p. 6 k
4. Whichofthefollowingmechanismsis(are)responsibleforthepossible
t t t t
association between oligohydramnios and lung hypoplasia?
k k k k k k
I. Abnormalcarbohydrate metabolism k
II. Mechanicalrestriction of the chest wall k k k k
III. Interferencewithfetal breathing k k
IV. Failureto produce fetal lungliquid k k k k k
a. Iand III only k k
b. IIand III only
k k k
c. I, II,and IV only
k k k k
d. II, III, and IVonly
k k k k
ANS: D k
Oligohydramnios, a reduced quantity of amniotic fluid present for an extended period oftime, k k k k k k k k k k k k t
with orwithout renal anomalies, is associatedwith lung hypoplasia. Themechanismsby which
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amniotic fluid volume influences lung growth remain unclear. Possibleexplanations for
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reducedquantityof amniotic fluid include mechanical restriction of thechest wall,
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interference with fetalbreathing, or failure to produce fetal lung liquid.
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Theseclinical and experimental observations possiblypoint to a common denominator,
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lungstretch, as being a major growth stimulant.
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REF: pp. 6-7
k k
5. What is the purpose of the substance secreted bythe type IIpneumocyte?
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