Developmental Lung Disease

Question 1

What are the stages of lung morphogenesis?

Answer 1

• Embryonic
• Pseudo-Glandular
• Canicular
• Saccular
• Alveolar

Question 2

What forms in the embryonic stage?

Answer 2

A laryngo-tracheal groove on the oesophagus which eventullay seperates into the trachea.

Question 3

What forms during the pseudo-glandular phase?

Answer 3

Bronchi form and seperate into the lobes that will eventually make up the lung.
Myofibroblasts and tubules form,
gas exchange isnt possible yet though.

Question 4

What occurs in the canalicular phase?

Answer 4

• Lot of cuboidal epithelium differentiates to squamous

- the blood vessel start to line the epithelium forming a blood-air barrier

Question 5

What kind of lung development occurs postnatal?

Answer 5

Further alveolar septation (formation essentially).

100-150mill at birth to 200-600mill at 3-8 years.

Question 6

At what stage of lung morphogenesis is surfactant produced?

Answer 6

IT becomes detectable in the saccular phase and is produced there and in the alveolar phase.

Question 7

What kind of things can go wrong in embryonic phase?

Answer 7

Tracheal Stenosis - Constriction/narrowing of the trachea either short or long segment.
Tracheo-oesophageal fistula - joining of the 2 tubes.
Pulmonary Agenesis - The lung bud doesnt form.

Question 8

What problems can occur in pseuoglandular phase?

Answer 8

• Cysts can form
• Pulmondary sequestration where part of the lung tissue is non-functioning and unconnected to the broncheal tree
• Cystadenomatoid malformation?

Question 9

At what point does the diaphragm close?

Answer 9

Around 18 weeks

Question 10

.On which side is a diaphragmatic hernia most likely?

Answer 10

Left

Question 11

.What can a hernia of the diaphragm cause?

Answer 11

Pulmonary hypoplasia - Essentially when thers an abnormally low number or size of bronchopulmonary segments.
Persistant pulmonary hypertension

Question 12

.What is eventration?

Answer 12

When the diaphragm muscle doesnt form properly and becomes weak eventually forming an unusual bulge and not contracting on inspiration. It often protudes upwards into the thorax

Question 13

.What functional changes occur in the lungs at birth?

Answer 13

From fluid secretion to absorption

Pulmonary vasodilation

Question 14

.What embryonic tissues contribute to the diaphragm?

Answer 14

Lots, a variety really

Question 15

.What embryonic tissue contributes to the airways?

Answer 15

The endoderm produces the epithelial cells of the trachea, pharynx and the alveolar cells.
This protudes into the mesoderm too

Question 16

Whats the main cause of COPD?

Answer 16

Heavy smoking

Question 17

What kind of fatalities does COPD cause?

Answer 17

Its the 2rd biggest killer int he world

Question 18

How do we treat a surfactant deficiency?

Answer 18

If we know a child wil be early we can stimulate the surfactant system early with antenatal glucocorticoids.
We can also use surfactant replacement, oxygen, mechanical ventilation and CPAP postnatal

Question 19

What is BronchoPulmonary Dysplasia (BPD)?

Answer 19

(Also Known as Chronic Lung Disease of Prematurity CLDP, or Chronic Neonatal Lung Disease)
A very severe bronchiolitis leads to alveolar damage, inflammation and scarring.
Makes them more likely to suffer COPD, Asthma and early life viral lung infections.

Question 20

What kind of fatalities does COPD cause?

Answer 20

Its the 3rd biggest killer in the world.

Question 21

What happens if you have low lung funciton in early life?

Answer 21

You are more at risk of future COPD. Whether its due to early infection, premature birth or Asthma.

Question 22

What are the antenatal origins of adult lung disease (COPD)?

Answer 22

• NIcotine exposure in utero
• Prematurity/low birth weight
• Nutrient/vitamin deficiency

Question 23

What is CPAP and why is it useful in treatment of a surfactant deficiency?

Answer 23

“Continuous Positive Airway Pressure”

All through the breathing cycle a positive presssure is appplied to the airways keeping them open and preventing alveolar collapse. Because its continuous the patient still has to initiate their own breaths.

Question 24

What 3 things influence remodelling of the aiway/lung parencyma during growth?

Answer 24

Antenatal programming
Enviromental exposures (e.g. nicotine)
Gene interactions

Question 25

What are some post-natal origins for adult lung disease COPD?

Answer 25

• Infections in early life are correlated to later COPD
• ETS (Enviromental tobacco smoke) exposure can lead to alpha1 AT deficiency which can cause emphysema/COPD
• Enviromental pollution, for instance if you live by a road
• Nutrient/vitamin deficiency