Embryology

Question 1

Which layer of the embryo does the lung bud originate from?

Answer 1

Endoderm

Question 2

Where does the lung bud come from?

Answer 2

The anterior upper part of the gut tube

Question 3

What grows together to separate the oesophagus from the trachea?

Answer 3

The tracheoesophageal ridge

Question 4

How are all respiratory congenital defects corrected?

Answer 4

Surgery

Question 5

What is the most common respiratory congenital defect?

Answer 5

A blind ending oesophagus from the mouth and a communication between the trachea and the oesophagus with the part coming from the stomach

Question 6

What is a blind ending of the oesophagus called?

Answer 6

Oesophageal atresia

Question 7

What is a communication between the trachea and the oesophagus called?

Answer 7

Tracheoesophageal fistula

Question 8

At what stage do the left and right primary bronchial buds form?

Answer 8

4 weeks

Question 9

At what stage do the secondary bronchial buds form?

Answer 9

30 days

Question 10

How many secondary bronchial buds form on the right and how many form on the left?

Answer 10

Right = 3
Left = 2

Question 11

At what stage do the tertiary bronchial buds form?

Answer 11

38 days

Question 12

What forms the visceral pleura and the tissue and cartilage surrounding the lung?

Answer 12

Visceral mesoderm

Question 13

What occurs in the embryonic stage of maturation of the lungs and what is the time period?

Answer 13

Time period = 26 days- 6 weeks

Respiratory diverticulum and branching to give lungs, lobes and segments

Question 14

What occurs in the pseudoglandular stage of maturation of the lungs and what is the time period?

Answer 14

Time period = 6-16 weeks

14 more generation of branching to form tertiary bronchioles

Question 15

What occurs in the canalicular stage of maturation of the lungs and what is the time period?

Answer 15

Time period = 16-28 weeks

Branching from the terminal bronchioles to at least 2 respiratory bronchioles

Question 16

What occurs in the saccular stage of maturation of the lungs and what is the time period?

Answer 16

Time period = 28-36 weeks

Terminal sacs form and the capillaries make close contact

Question 17

What occurs in the alveolar stage of maturation of the lungs and what is the time period?

Answer 17

Time period = 36 weeks into infancy

Alvioli mature

Question 18

What type of cells produce surfactant?

Answer 18

Type 2 pneumocytes (cuboidal)

Question 19

What is the role of sufactant?

Answer 19

Reduces alviolar surface tension preventing alveolar collapse.

Question 20

Why do premature babies experience Acute Respiratory Distress Syndrome (ARDS)?

Answer 20

Type 2 pneumocytes are some of the last cells to develop therefore premature babies often do not produce enough surfactant and their alvioli are prone to collapse making it difficult for them to expand their lungs fully.