Embryology of the respiratory system

Question 1

What does the endoderm of the lung bud give rise to?

Answer 1

epithelium of larynx, trachea, bronchi and bronchioles and the pulmonary lining epithelium

Question 2

What does the splanchnic mesoderm give rise to?

Answer 2

connective tissue, cartilage and smooth muscle of the trachea and lungs

Question 3

Where are the laryngeal cartilages derived from?

Answer 3

fourth and sixth laryngeal arches

Question 4

What is the septum transversum?

Answer 4

visceral mesoderm surrounding the embryonic heart between thoracic and abdominal cavities

Question 5

What 4 structures is the diaphragm derived from?

Answer 5

septum transversum
pleuroperitoneal membranes
dorsal mesentery of the oesophagus
body wall muscles cells

Question 6

What are the 4 stages of lung maturation and development?

Answer 6

pseudoglandular (5-17 weeks)
canalicular (16-25 weeks)
saccular (24 weeks - birth)
alveolar (late fetal period - ~8 years)

Question 7

Function of type 1 alveolar cells

Answer 7

gas exchange

Question 8

Function of type 2 alveolar cells

Answer 8

produce surfactant
decreased surface tension at air-alveolar interface

Question 9

What week of pregnancy is adequate surfactant produced?

Answer 9

32nd week

Question 10

What causes respiratory distress syndrome in premature babies?

Answer 10

insufficient surfactant
increased surface tension = collapse of alveoli = atelectasis

Question 11

Name the 4 paranasal sinuses

Answer 11

frontal sinus
ethmoid sinus
sphenoid sinus
maxillary sinus