Fetal and newborn pulmonary physiology Flashcards

1
Q

when does alveolar formation begin?

A

28th week gestation

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2
Q

what are the milestone phases of lung development?

A
embryonic 
psueoglandular 
canalicular 
saccular 
alveolar
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3
Q

during what week does surfactant start being produced? during which phase of lung development is this?

A

25th week

saccular

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4
Q

what events occur during the embryonic phase of lung development?

A

first segments appear in the 5 lobes

pulmonary vessels have formed

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5
Q

during which phase of lung development can precursors of pneumocytes be discerned in the respiratory sections as cubic epithelium?

A

pseudoglandular

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6
Q

during which phase do type I pneumocytes differentiate from type II pneumocytes?

A

canalicular

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7
Q

during which phase is amniotic fluid produced by lung epithelium?

A

canalicular

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8
Q

at what point can lung maturity be based upon the activity of type II pneumocytes?

A

from canalicular phase onward

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9
Q

what is the main feature of the saccular phase of lung development?

A

whole clusters of sacs form on the terminal bronchioli

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10
Q

phase: primary septa contain two networks of capillaries coming from neighboring sacculi

A

saccular phase

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11
Q

phase: fibroblasts begin to produce extracellular material in the interductal and intersaccular space

A

saccular phase

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12
Q

by the end of which phase have all generations of conducting and respiratory branches been generated?

A

saccular

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13
Q

the onset of functional maturation of the lung is marked by the appearance of what structures? where are they located?

A

lamellar bodies

alveolar type II cells

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14
Q

the ratio of what compounds in amniotic fluid is a measure of fetal lung maturity?

A

lecithin / sphingomyelin

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15
Q

what happens to the lecithin / sphingomyelin ratio at week 32?

A

lecithin production increases rapidly

sphingomyelin production decreases

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16
Q

a lecithin / sphingomyelin ratio below what value indicates poor lung maturity?

A

1.8

17
Q

what are the functions of surfactant specific proteins?

A

immune defense

surface activity

18
Q

which surfactant specific proteins are critical for surface activity?

A

SP-B

SP-C

19
Q

what are stimulators of surfactant synthesis in the saccular phase of lung development?

A
glucocorticoids 
thyroid hormones 
cAMP 
epidermal growth factor 
beta adrenergic agonists 
purinoceptor agonists
20
Q

what is an inhibitor of surfactant synthesis in the saccular phase of lung development?

A

maternal diabetes

21
Q

what events occur in late fetal life during the alveolar maturation phase of lung development?

A

increase number and size of alveoli
thinning of CT septa between alveoli
flatter alveolar epithelium

22
Q

what is the role of the perinatal EPI surge?

A

activates transepithelial sodium transport to absorb all the fluid in the lungs

23
Q

perinatal absorption of lung fluid is enhanced by what factors?

A

thyroid and steroid hormones

alveolar capillary pressure gradient

24
Q

what is the status of neonatal lung compliance?

A

low static and dynamic compliance:

low lung compliance
high chest wall compliance
viscous properties of newborn lung tissues
distortion of pliable newborn chest

25
Q

what is the status of neonatal nasal resistance?

A

low

26
Q

what is the status of neonatal airway resistance?

A

high

27
Q

term infant respiratory function in the first hour of life: lung compliance

A

increase

28
Q

term infant respiratory function in the first hour of life: lung resistance

A

decrease

29
Q

term infant respiratory function in the first hour of life: functional residual capacity

A

increase

30
Q

term infant respiratory function in the first hour of life: breathing frequency

A

increase

31
Q

term infant respiratory function in the first hour of life: tidal volume

A

decrease then plateau

32
Q

term infant respiratory function in the first hour of life: arterial pO2

A

increase

33
Q

term infant respiratory function in the first hour of life: arterial pCO2

A

decrease

34
Q

what happens to the pulmonary arteries : alveoli ratio after birth? what is the effect?

A

decreased

decreasing vascular resistance

35
Q

what is the importance of arousal in neonatal respiratory control?

A

changes breathing pattern from episodic to continuous