Developmental aspects of lung disease

Question 1

Name the 5 main stages of lung morphogenesis

Answer 1

Embryonic 
pseudo-glandular 
canalicular 
saccular 
Alveolar

Question 2

Roughly state when these 5 stages occur

Answer 2

3-8 weeks
5-17 weeks 
16-26 weeks 
24-38 weeks 
36 weeks to 2/3 years old

Question 3

What is the trachea laryngeal groove a precursor for?

Answer 3

Trachea and larynx

Question 4

Liquid from where moves to the oesophagus to create amniotic fluid?

Answer 4

Primary bronchial tubule

Question 5

What does the tissue in the pseudo glandular phase resemble?

Answer 5

Adult glandular tissue which is metabolically active eg thyroid

Question 6

How many branches do you end up with off the primitive trachea?

Answer 6

21

Question 7

Can gas exchange occur in the pseudo galndular phase?

Answer 7

No - the tubes are still fluid filled

Question 8

What do myofibroblasts do?

Answer 8

Add cartilage

Question 9

Is gas exchange possible at the end of the canicular phase?

Answer 9

Yes as the squamous epithelium and the blood vessels are close

Question 10

Describe the texture and structure of airways in the canicular phase

Answer 10

They are less of a solid structure and are more spongy and getting thinner

Question 11

Quickly state what happens in the saccular and alveolar stages

Answer 11

Saccular - more sacs form

Alveolar - alveoli at around 36 weeks

Question 12

State the rise in the number of alveoli after birth

Answer 12

100-150M to 200-600M at 3-8 years old

Question 13

After 3-8 years old do you still produce more alveoli?

Answer 13

No, they only increase in diameter from then on

Question 14

Name the 3 embryonic stage diseases

Answer 14

Tracheal, laryngeal stenosis
Pulmonary agenesis
Tracheo- oesophageal fistula

Question 15

Tracheal, laryngeal stenosis

Answer 15

Narrowing of windpipe

Question 16

Pulmonary agenesis

Answer 16

Complete absence of a lung lobe or its branch

Question 17

Tracheo- oesophageal fistula

Answer 17

Trachea and oesophagus do not separate

Question 18

Name the 3 pseudoglandular stage diseases

Answer 18

Pulmonary sequestration
Cystodenomatoid malformation
cyst formation

Question 19

Pulmonary sequestration

Answer 19

Extra piece of lung in the wrong place

Question 20

Cystodenomatoid malformation

Answer 20

Entire lobe replaced by cyst

Question 21

Describe briefly how the diaphragm is formed

Answer 21

Primitive tissues meet and fuse

Closure by about 18 weeks

Question 22

Diaphragmatic hernia

Answer 22

Bowel move sup to the chest which means the lung on that side does not develop properly - pulmonary hypoplasia and persistent pulmonary hypertension

Question 23

Eventration

Answer 23

Incomplete muscularisation of the diaphragm

Question 24

State the 2 functional changes in the lug after birth

Answer 24

Change from fluid secretion to fluid absorption

Pulmonary vasodilation -> oxygen

Question 25

Transient tachypnea

Answer 25

Breathe faster due to retained lung fluid

Premature or C section babies usually

Question 26

Name the 2 constituents of surfactant

Answer 26

Phospholipids and lipophilic proteins

Question 27

When is surfactant produced?

Answer 27

12-14 weeks

Question 28

Hyaline membrane disease

Answer 28

Small alveoli collapse giving granular appearance

Question 29

Name the 5 forms of treatment for RDS

Answer 29

antenatal glucocorticoids 
oxygen 
CPAP - continuous positive airway pressure 
Surfactant replacement 
Mechanical ventilation

Question 30

What can chronic lung disease lead to?

Answer 30

Increased severity of bronchiolitis

Asthma and possible future COPD

Question 31

Where does COPD come in the leading causes of death?

Answer 31

Third

Question 32

Antenatal fetal origins of COPD

Answer 32

In utero nicotine, prematurity and birth weight, nutrition and vitamins

Question 33

Postnatal origins of COPD

Answer 33

Infection, growth, diet, environment