Embryoloy & Histology

Question 1

What derm layer do the lungs grow from and into?

Answer 1

From the ENDODERM

Grow into the mesoderm

Question 2

What structure do the lungs bud off?

Answer 2

Oesophagus

Question 3

What do the secondary and tertiary bronchial buds give rise to?

Answer 3

Secondary - lobar bronchi

Tertiary - segmental bronchi

Question 4

What are the two most common birth defects in resp system?

Answer 4

Oesophageal atresia
Tracheosophageal fistula (common)

Question 5

Name the five stages of maturation of the lungs and their timeframe. 
E
P
C
S
A

Answer 5

Embryonic: 26 days - 6 weeks
Pseudoplandular: 6 - 16 weeks
Canalicular: 16-28 weeks
Saccular: 28-36 weeks
Alveolar: 36 weeks - early childhood

Question 6

What are the two linings of the nasal cavity?

Answer 6

Initially in the vestibule, there is keratinised stratified squamous epithelium, deeper in the keratin is lost

Question 7

What is respiratory epithelium?

Answer 7

Pseudostratified ciliated columnar epithelium with goblet cells.

Question 8

The lamina propria lies under the respiratory epithelium in the nasal cavity.
What tissue makes up the lamina propria?
What does it contain?

Answer 8

Connective tissue

Contains seromucous glands and a rich venous plexus which can quickly engorge with blood and “block” the nose

Question 9

How does the shape of the epithelium change as you move down the respiratory tract?

Answer 9

Moves from columnar to cuboidal