Lung development

Question 1

What is the embryonic stage?

Answer 1

3-8 weeks

Question 2

What is the pseudo glandular stage

Answer 2

5-17 weeks

Question 3

what is the canalicular stage?

Answer 3

16-26 weeks

Question 4

what is the saccular stage?

Answer 4

24-38 weeks

Question 5

what is the alveolar stage?

Answer 5

36 weeks- 2/3 years

Question 6

Pulmonary hypertension in chronic respiratory disease occurs due to chronic hypoxia.

Select one:

True

False

Answer 6

True – hypoxia triggers a reflex constriction of pulmonary vessels, and this constriction increases the vascular resistance and therefore the pressure of the pulmonary circulation.

Question 7

what phase does lung bug develop first as a bud and where from?

Answer 7

in the embryonic phase via fetal foregut

Question 8

The embryonic lung buds are derived from the foregut.

Select one:

True

False

Answer 8

True – the lungs begin as an outpouching of the foregut, hence the close proximity of the trachea to the oesophagus.

Question 9

at how many weeks are there 2 primary lung buds visible?

what does this make?

Answer 9

5 weeks

this makes the lobar buds = 3 on right 2 on left

Question 10

the cells of the lung are derived from

Answer 10

like cells of the gut, lung cells are derived from endotherm

Question 11

blood vessels and tissues are derived from what type of cell?

Answer 11

blood vessels connective tissues surrounded by mesoderm

Question 12

what embryonic phase for lung development is at 5-17 weeks?

Answer 12

pseudoglandular phase - lung morphogenesis

Question 13

how many weeks is the pseudo glandular phase in embryology for lung development

Answer 13

5-17 weeks

Question 14

what happens to the lungs at the pseudo glandular stage of embryonic lung development?

Answer 14

rapid branching of the airway

16-25 primitive segmental bronchi which continue to elongate

specialising cilia and mucus glands appear airways

Question 15

Which phase involves the lung developing distal architecture

Answer 15

canalicular 16-26 weeks

Question 16

canalicular stage what is formed

Answer 16

type 1 and type 2 pneumocytes form a very thin membrane

Question 17

in the later phase of canalicular what happens?

Answer 17

specialised cells mature which allows a baby to survive successfully if born prematurely with intensive care support

Question 18

how many weeks can an infant be to survive

Answer 18

24 weeks. especially with improves natal care.

even 22 and 24 weeks although high-risk morbidity and mortality.

Question 19

saccular stage 24-38 weeks

Answer 19

become alvioli after birth form well. more surfactant produces. bronchioles elongate interstitial tissue between sac reduced alveolar walls become thinner to improve gas exchange

Question 20

alveolar stage 26 weeks - term and 2 years

Answer 20

lungs independently sustain breathing without support cells well differentiated

pulmonary vasculature well developed forming final alveolar structures

Question 21

healthy foetus how many airsacs

Answer 21

20-50 million at birth and 200-30 million age 3-8

Question 22

common upper respiratory congenital abnormalities respiratory

Answer 22

Pierre-robin sequence; choanal stenosis/atresia

laryngomalacia and tracheomalacia; treacheo-oesophageal fistula

laryngeal atresia; tracheal atresia and stenosis; laryngeal web and cyst

*Atresia is a condition in which an orifice or passage in the body is (usually abnormally) closed or absent.*

Question 23

common lower respiratory congenital abnormalities respiratory

Answer 23

pulmonary hypoplasia

bronchogenic cyst

CPAM

congenital diaphragmatic hernia

bronchial atresia and stenosis

Question 24

how are gongenital respiratory abnormalities usually picked up?

antenatal

Answer 24

antenatal scanning

• ultrasound

MRI (fetal)

Question 25

symptoms of congenital respiratory abnormalities newborn

Answer 25

tachypnoea

respiratory distress

feeding issues

Question 26

symptoms of congenital respiratory abnormalities child

Answer 26

stridor/wheeze

recurrent pneumonia

cough

feeding issues

Question 27

describe laryngomalacia

Answer 27

malacia (softening) - softening of the voice box

commonly seen in infants

presents with stridor, worse when feeding or when upset/excited

will improve in the first year

only concern if child struggles to feed, growth or colour change

Question 28

tracheomalcia

Answer 28

malacia (softening) of the trachea

can be isolated in healthy infants

associated with genetic conditions

maybe caused by external compression (e.g. vessels/tumour)

• bronchoscopy to find
  presentation: barking cough, recurrent croup, breathless on exertion, stridor/wheeze

usually resolved on own, may need physio and antibiotics if unwell.

Question 29

tracheo-oesophageal fistula

Answer 29

• abnormal connection between trachea and oesophagus

the majority have associated with oesophageal atresia (closing)

association genetic conditions

presentation: normally diagnosed antenatally or postnatally: choking colour change cough when feeding unable to pass ng tube
treatment: surgical repair
complications: tracheomalacia, strictures, leak and reflux

Question 30

congenital pulmonary airway malformation (CPAM)

Answer 30

• abnormal non-functioning lung tissue; - 80%detected antenatally;
• occurs sporadically -many resolve spontaneously in utero
• conservative if asymptomatic
• surgical intervention may be required - possible risk of malignant change

Question 31

congenital diaphragmatic hernia

Answer 31

the diaphragm forms from multiple tissues around 7 weeks and closes by 18 weeks

CHD affects 1 in 2500 births different typed most common bochdalek 90%

usually left side more common than the right side

most diagnosed antenatally some cases late diagnoses (earlier the better)

need to be transferred to ITU due to significant morbidity and mortality

surgical repair prognosis depends on degree of lung hypoplasia

Question 32

where can lung remodelling of the lung can occur (child development)

Answer 32

seen in asthma and chronic lung disease of prematurity

Chronic inflammation - increased bronchial responsiveness

increase mucus secretion

airway oedema

airway narrowing