Embryology 3 - Development of resp system

Question 1

How far into gestation do the trachea and lungs begin to develop?

Answer 1

4 weeks in

Question 2

From what area do the trachea and lungs develop?

Answer 2

Ventral wall of the foregut

Development begins with formation of larygo-tracheal groove

Question 3

The first stage of development of the respiratory system is the…

Answer 3

Formation of larygo-tracheal groove from the ventral part of the foregut - pharynx area

Question 4

Describe how the trachea separates from the oesophagus

Answer 4

The oesophagotracheal septum develops develops between the oesophagus and the trachea and eventually separates them

Question 5

What is a fistula?

Answer 5

Abnormal or surgically made passage between a tubular organ and the body surface, or between two hollow or tubular organs

Question 6

Give an example of a fistula

Answer 6

Tracheoesophageal fistula

Question 7

What is an atresia?

Answer 7

A condition in which an oriface or passage in the body is closed or absent

Question 8

What is the parietal pleura derived from?

Answer 8

Somatic mesoderm

Question 9

What is the visceral pleura derived from?

Answer 9

Splanchnic mesoderm

Question 10

Describe how the pleura and pleural cavity are formed

Answer 10

The lungs begin to develop and ‘punch’ into the splanchnic mesoderm, so they acquire a layer a visceral pleura from the splanchnic mesoderm

The thoracic wall becomes lined by the somatic mesoderm which forms the parietal pleura

The space between the parietal and visceral pleura is the pleuropericardial canals (this becomes the pleural cavity)

Question 11

What are the stages of lung development?

Answer 11

Embryonic 4-7 
Pseudoglandular 7-17
Canalicular 17-27
Saccular 27-40
Alveolar - post-natal

Question 12

What is surfactant made of?

Answer 12

Phospholipids and proteins

Question 13

What is RDS?

Answer 13

Respiratory distress syndrome (aka hyaline membrane disease HMD)

Surfactant deficiency is a major cause of RDS

Question 14

How many neonates suffer from RDS?

Answer 14

2% of neonates affected

30% of neonatal disease

Question 15

What are the main neonatal congenital conditions with development of the lungs?

Answer 15

RDS

Accessory lobes

Azygos lobe

Agenesis of lung

Question 16

The septum transversum forms the ______

Answer 16

Central tendon of the diaphragm

Question 17

The Pleuroperitoneal membranes form the _____

Answer 17

primitive diaphragm

Question 18

The Dorsal mesentery of oesophagus forms the ______

Answer 18

median portion & crura of diaphragm

Question 19

The Muscular ingrowth from lateral body walls forms the ______

Answer 19

peripheral parts of diaphragm

Question 20

Describe the development and movement of the septum tranversum during foetal development

Answer 20

ST initially located opposite the C3-C5 somites (week 3)

It migrates caudally during the development of the diaphragm and takes down the spinal nerves from C3-C5 with it

(These spinal nerves = the phrenic nerve)

Question 21

What are the major congenital abnormalities with the development of the diaphragm?

Answer 21

• Failure to completely close during development
• Herniation of abdominal contents into chest
• Pulmonary hypoplasia

Question 22

What is a herniation?

Answer 22

Bulge/protrusion of an organ through the structure/muscle which should contain it

Question 23

What 2 basic types of hernia’s can take place with the diaphragm?

Answer 23

Diaphragmatic hernia

Hiatal hernia

Question 24

The somatic mesoderm forms _____

Answer 24

Parietal pleura

Question 25

The splanchnic mesoderm forms _____

Answer 25

Visceral pleura