Embryology of respiratory system

Question 1

when does resp system start developing?

Answer 1

day 26

Question 2

larynx embryology facts?

Answer 2

is completely formed by week 12
is formed from the pharyngeal arches 4-6
and is formed from all 3 germ layers

Question 3

lung maturation stages

Answer 3

formation of tracheoesophgeal Ridges
pseudoglandular stage
canalicular period 
terminal sac stage
alveolar stage

Question 4

pseduglandular stage, in one sentence

Answer 4

weeks 6-16

formation of resp tree up to terminal bronchioles

Question 5

canalicular stage?

Answer 5

weeks 16-28

Pulmonary capillaries start forming, continuation of resp tree up to primitive alveoli formation

Question 6

what is primitive alveoli?

Answer 6

immature and cubiodal lined

Question 7

terminal sac stage?

Answer 7

week 28 - 36
more primitve alveoli forms
primitve alveoli epithelium starts deffrentiating into pnemocytes and surfactant is produced
and blood air barrier forms

Question 8

alveolar stage?

Answer 8

week 36 -8 years
septa formation
muscles of breathing start working in womb
and this overlaps with terminal sac stage

Question 9

possible genetic defects in the formation of tracheoesophgeal Ridges

Answer 9

• oesophageal atresia (oesophagus not reaching stomach)

- tracheoesophgeal fistula (communication between them)

Question 10

surfactant defect?

Answer 10

low surfactant can cause RDS and 20% newborn deaths