Embryology of the Respiratory System

Question 1

Where is the origin of the lung? (the lung bud)

Answer 1

Cranial end of the gut tube

Question 2

What forms the lining of the respiratory tree?

Answer 2

Mesoderm

Question 3

The lung, as it grows, becomes surrounded by _____

Answer 3

visceral mesoderm

Question 4

What forms all the smooth muscle cartilage and all other lung tissue besides the lining of the trachea & bronchial tree within the lungs?

Answer 4

Mesoderm

Question 5

During embryological development there is ___ communication between the respiratory and digestive tract

Answer 5

decreasing

Question 6

What will result from failure of division of the oesophagus and trachea?

Answer 6

Abnormal communication

Question 7

What is the name of abnormal communication between trachea and oesophagus?

Answer 7

Tracheoesophageal fistula

Question 8

Which maturation period of the lungs occurs between day 26 and week 6?

Answer 8

Embryonic

Question 9

What occurs during the embryonic maturation period of the lungs?

Answer 9

Respiratory diverticulum forms

Initial branching to give lungs, lobes and segments

Question 10

Which phase of maturation of the lungs occurs between week 6 and 16?

Answer 10

Pseudo glandular

Question 11

What occurs during the pseudo glandular phase of maturation?

Answer 11

14 more generations of breaching: Terminal bronchioles

Question 12

Which period of maturation of the lungs occurs between week 16 and 28?

Answer 12

Canalicular

Question 13

What occurs during the canalicular period of maturation of the lungs?

Answer 13

Terminal bronchioles divide to form 2+ respiratory bronchioles –> divide into 3-5 alveolar ducts

Question 14

When does the saccular period of maturation of the lungs occur?

Answer 14

Week 28-36

Question 15

What occurs during the period of week 28-36 during maturation of the lungs?

Answer 15

Terminal sacs form, capillaries establish close contact

Question 16

When does alveolar maturation of the lungs take place?

Answer 16

36 week - early childhood

Question 17

Which type of epithelium do the conducting bronchioles initially have?

Answer 17

Cuboidal epithelium

Question 18

What does cuboidal epithelium in developing alveoli differentiate into?

Answer 18

Type I and Type II Pneumocytes

Question 19

What is the function of type II pneumocytes?

Answer 19

To produce surfactant to decrease water’s surface tension and prevent lung collapse

Question 20

What is the function of type I pneumocytes?

Answer 20

Blood-air barrier

Question 21

Why is respiratory distress syndrome common in prematurely born babies?

Answer 21

Surfactant production doesn’t begin until late in pregnancy