Lung development Flashcards
What is the embryonic stage?
3-8 weeks
What is the pseudo glandular stage
5-17 weeks
what is the canalicular stage?
16-26 weeks
what is the saccular stage?
24-38 weeks
what is the alveolar stage?
36 weeks- 2/3 years
Pulmonary hypertension in chronic respiratory disease occurs due to chronic hypoxia.
Select one:
True
False
True – hypoxia triggers a reflex constriction of pulmonary vessels, and this constriction increases the vascular resistance and therefore the pressure of the pulmonary circulation.
what phase does lung bug develop first as a bud and where from?
in the embryonic phase via fetal foregut
The embryonic lung buds are derived from the foregut.
Select one:
True
False
True – the lungs begin as an outpouching of the foregut, hence the close proximity of the trachea to the oesophagus.
at how many weeks are there 2 primary lung buds visible?
what does this make?
5 weeks
this makes the lobar buds = 3 on right 2 on left
the cells of the lung are derived from
like cells of the gut, lung cells are derived from endotherm
blood vessels and tissues are derived from what type of cell?
blood vessels connective tissues surrounded by mesoderm
what embryonic phase for lung development is at 5-17 weeks?
pseudoglandular phase - lung morphogenesis
how many weeks is the pseudo glandular phase in embryology for lung development
5-17 weeks
what happens to the lungs at the pseudo glandular stage of embryonic lung development?
rapid branching of the airway
16-25 primitive segmental bronchi which continue to elongate
specialising cilia and mucus glands appear airways
Which phase involves the lung developing distal architecture
canalicular 16-26 weeks
canalicular stage what is formed
type 1 and type 2 pneumocytes form a very thin membrane
in the later phase of canalicular what happens?
specialised cells mature which allows a baby to survive successfully if born prematurely with intensive care support
how many weeks can an infant be to survive
24 weeks. especially with improves natal care.
even 22 and 24 weeks although high-risk morbidity and mortality.
saccular stage 24-38 weeks
become alvioli after birth form well. more surfactant produces. bronchioles elongate interstitial tissue between sac reduced alveolar walls become thinner to improve gas exchange
alveolar stage 26 weeks - term and 2 years
lungs independently sustain breathing without support cells well differentiated
pulmonary vasculature well developed forming final alveolar structures
healthy foetus how many airsacs
20-50 million at birth and 200-30 million age 3-8
common upper respiratory congenital abnormalities respiratory
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.*
common lower respiratory congenital abnormalities respiratory
pulmonary hypoplasia
bronchogenic cyst
CPAM
congenital diaphragmatic hernia
bronchial atresia and stenosis
how are gongenital respiratory abnormalities usually picked up?
antenatal
antenatal scanning
- ultrasound
MRI (fetal)
symptoms of congenital respiratory abnormalities newborn
tachypnoea
respiratory distress
feeding issues
symptoms of congenital respiratory abnormalities child
stridor/wheeze
recurrent pneumonia
cough
feeding issues
describe laryngomalacia
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
tracheomalcia
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.
tracheo-oesophageal fistula
- 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
congenital pulmonary airway malformation (CPAM)
- 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
congenital diaphragmatic hernia
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
where can lung remodelling of the lung can occur (child development)
seen in asthma and chronic lung disease of prematurity
Chronic inflammation - increased bronchial responsiveness
increase mucus secretion
airway oedema
airway narrowing
