Developmental Aspect of Lung Disease

Question 1

At what weeks of gestation does the embryonic lung development phase span?

Answer 1

3 - 8 weeks

Question 2

What happens first during the embryonic phase?

Answer 2

Lung offshoots off the foregut

Question 3

What germ layer does the lung grow into?

Answer 3

Mesoderm

Question 4

What does the primary bronchial tube act as at this point?

Answer 4

A gland

Question 5

What does the bronchial tube gland secrete into?

Answer 5

Amniotic fluid

Question 6

At this point, how close do blood vessels lie to airways?

Answer 6

Far away

Question 7

What stage follows the embryonic stage and how long does it last?

Answer 7

• Pseudo glandular - 5 - 17 weeks

Question 8

What starts to form at the pseudo glandular phase?

Answer 8

• Very early lung
• Lobes become obvious

Question 9

What starts to form in the bronchioles during the pseudoglandular phase?

Answer 9

Myofibrils

Question 10

How much metabolic activity occurs during the pseudoglandular phase?

Answer 10

Lots

Question 11

Describe the image relating to A) blood vessel position B) glandular aspect C) myofibrils

Answer 11

A) still far away from airways

B) acinar tubules widely branching

C) myofibrils forming around bronchioles

Question 12

What is the next phase in lung development following the pseudoglandular and how long does it last?

Answer 12

• Canalicular
• 16 - 26 weeks

Question 13

What is the main formation during the canalicular phase?

Answer 13

• Squamous epithelium forms

Question 14

What does the formation of the squamous epithelium during the canalicular phase allow?

Answer 14

Gas exchange to be possible

Question 15

What else occurs during the canalicular phase to allow gas exchange to occur?

Answer 15

Blood vessels move closer to the saccules

Question 16

What phase follows the canalicular phase and how long does it last?

Answer 16

• Saccular
• 24 - 38 weeks

Question 17

What occurs during the saccular phase?

Answer 17

More saccules form

Question 18

What phase begins at 36 weeks and can last 2/3 years after birth?

Answer 18

Alveolar phase

Question 19

What happens to the saccules during the alveolar phase?

Answer 19

They turn into alveoli

Question 20

What fills the alveoli during gestation?

Answer 20

Fluid

Question 21

What is the name given to the separation of alveoli into segments?

Answer 21

Alveolar Septation

Question 22

How many alveoli does the average human start life with?

Answer 22

100 - 150 million

Question 23

How many alveoli does the average human have after septation?

Answer 23

200 - 600 million

Question 24

STUDY THE FOLLOWING DIAGRAM

Answer 24

Question 25

When does surfactant begin to form?

Answer 25

Around 24 weeks

Question 26

STUDY THE FOLLOWING DIAGRAM

Answer 26

Question 27

What is tracheal/laryngeal stenosis?

Answer 27

Abnormal narrowing of the main airways

Question 28

What is pulmonary agenesis?

Answer 28

Failure of lung development during the embryonic stage

Question 29

What is tracheo-oesophageal fistula?

Answer 29

Where the oesophagus infringes onto the trachea and they join together

Question 30

What is pulmonary sequestration?

Answer 30

When their is a functioning mass of normal lung tissue that has no link to the main airways

Question 31

What is cystadenamatoid malformation?

Answer 31

Areas of the lung that are solid or fluid filled masses that can have an effect on breathing

Question 32

What does congenital mean?

Answer 32

Present at birth

Question 33

What does the diaphragm start off as in development?

Answer 33

Tissue that fuses with the abdominal wall

Question 34

When does closure of the diaphragm occur?

Answer 34

18 weeks

Question 35

What can cause a diaphragmatic hernia during development?

Answer 35

Pulmonary hypoplasia - the diaphragm will infinge into the space where the lung should be

Question 36

What does eventration mean with reference to the diaphragm?

Answer 36

Some areas are more dense than others

Question 37

What functional change occurs during the first few breaths of life?

Answer 37

The lungs change from fluid secretion to fluid absorption to get rid of the fluid filling the airways

Question 38

What can result if the functionality of the lung is unable to change to fluid absorption?

Answer 38

Wet lung - acute respiratory distress

Question 39

What happens to the blood vessels around the alveoli during the first few breaths

Answer 39

Pulmonary vasodilation

Question 40

What does surfactant act as?

Answer 40

A detergent

Question 41

When do type 2 pneumocytes appear during development?

Answer 41

12 - 14 weeks

Question 42

What is the name of the disease given to a surfactant deficiency?

Answer 42

Hyaline Membrane Disease

Question 43

How is hyaline membrane disease treated?

Answer 43

- Antenatal glucorticoids - Surfactant replacement - High conc. oxygen - Mechanical ventilation

Question 44

What are 2 examples of chronic neonatal lung diseases?

Answer 44

- Bronchopulmonary dysplasia - Chronic lung disease of prematurity

Question 45

What are the antenatal origins of adult lung disease?

Answer 45

- In utero exposure to nicotine - Nutrition - Prematurity

Question 46

How does smoking affect FEV?

Answer 46

Decreases it

Question 47

If someone is born with poor lung function, what does it increase the risk of developing later in life?

Answer 47

COPD

Question 48

http://www.columbia.edu/itc/hs/medical/humandev/2004/Chpt12-LungDev.pdf