Fetal and newborn pulmonary physiology Flashcards Preview

Year 2 Respiratory > Fetal and newborn pulmonary physiology > Flashcards

Flashcards in Fetal and newborn pulmonary physiology Deck (35)
1

when does alveolar formation begin?

28th week gestation

2

what are the milestone phases of lung development?

embryonic
psueoglandular
canalicular
saccular
alveolar

3

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

25th week

saccular

4

what events occur during the embryonic phase of lung development?

first segments appear in the 5 lobes
pulmonary vessels have formed

5

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

pseudoglandular

6

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

canalicular

7

during which phase is amniotic fluid produced by lung epithelium?

canalicular

8

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

from canalicular phase onward

9

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

whole clusters of sacs form on the terminal bronchioli

10

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

saccular phase

11

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

saccular phase

12

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

saccular

13

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

lamellar bodies

alveolar type II cells

14

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

lecithin / sphingomyelin

15

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

lecithin production increases rapidly

sphingomyelin production decreases

16

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

1.8

17

what are the functions of surfactant specific proteins?

immune defense
surface activity

18

which surfactant specific proteins are critical for surface activity?

SP-B
SP-C

19

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

glucocorticoids
thyroid hormones
cAMP
epidermal growth factor
beta adrenergic agonists
purinoceptor agonists

20

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

maternal diabetes

21

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

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

22

what is the role of the perinatal EPI surge?

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

23

perinatal absorption of lung fluid is enhanced by what factors?

thyroid and steroid hormones
alveolar capillary pressure gradient

24

what is the status of neonatal lung compliance?

low static and dynamic compliance:

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

25

what is the status of neonatal nasal resistance?

low

26

what is the status of neonatal airway resistance?

high

27

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

increase

28

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

decrease

29

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

increase

30

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

increase

31

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

decrease then plateau

32

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

increase

33

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

decrease

34

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

decreased

decreasing vascular resistance

35

what is the importance of arousal in neonatal respiratory control?

changes breathing pattern from episodic to continuous