embryology of the respiratory system

Question 1

where does the laryngotracheal groove bud from?

Answer 1

the foregut

Question 2

what does the laryngotracheal tube develop into?

Answer 2

trachea and lung buds

Question 3

how is the laryngotracheal tube and the oesophagus separated?

Answer 3

the oesophagotracheal septum grows between the two tubes

Question 4

what is another name for the laryngotracheal groove?

Answer 4

diverticulum

Question 5

which embryonic structure forms the central tendon of the diaphragm?

Answer 5

the septum transversium

Question 6

explain why the diaphragm has innervation from C3, 4 and 5?

Answer 6

the septum transversium originates from the cervical region of the embryo and migrates down to its final level. When it does this it drags its nerve supply with it forming the phrenic nerve

Question 7

at what week of gestation does the embryo fold?

Answer 7

week 3

Question 8

at what stage of gestation does the diverticulum form?

Answer 8

week 4

Question 9

what is a fistula?

Answer 9

an abnormal or surgically made passage between a hollow or tubular organ and the body surface, or between two hollow or tubular organs, ie. between 2 epithelialized surfaces.

Question 10

what is a tracheoesophageal fistula?

Answer 10

a passage between the trachea and the oesophagus

Question 11

what is atresia?

Answer 11

a condition in which an orifice or passage in the body is (usually abnormally) closed or absent.

Question 12

what embryonic structure gives rise to the visceral pleura?

Answer 12

the splanchnic mesoderm (splanchnopleure)

Question 13

what embryonic structure gives rise to the parietal pleura?

Answer 13

the somatic mesoderm (somatopleure)

Question 14

what separates the pleural cavities from the pericadial cavity?

Answer 14

pleuropericardial folds

Question 15

what is the gap between the parietal and visceral pleura called (before the diaphragm is formed completely)?

Answer 15

the pericardioperitoneal canal

Question 16

what do the lung buds differentiate in to as they proliferate?

Answer 16

visceral (splanchnic) mesoderm into the pericardioperitoneal canals

Question 17

what are the 5 stages if differentiation of lung buds?

Answer 17

embryonic
pseudoglandular
canalicular
saccular
alveolar

Question 18

when does the majority of the alveolar stage of lung development occur?

Answer 18

postnatally

Question 19

what are some congenital conditions of the lungs?

Answer 19

• RDS
• accessory lobe (extra lobe)
• azygos lobe (azygous vein infiltrates lung to give the appearance of an extra lung)
• agenesis of lung (lung does not form

Question 20

what are the 4 embryonic components of the diaphragm?

Answer 20

• septum transversium
• pleuroperitoneal membranes
• dorsal mesentary of oesophagus
• muscular ingrowth from lateral body walls

Question 21

what part of the diaphragm does the septum transversium form?

Answer 21

the central tendon

Question 22

what part of the diaphragm do the pleuroperitoneal membranes form?

Answer 22

the primitive diaphragm

Question 23

what part of the diaphragm does the dorsal mesentery of the oesphagus form?

Answer 23

median portion and crura

Question 24

what part of the diaphragm does the muscular ingrowth from the lateral body walls form?

Answer 24

peripheral parts of the diaphragm

Question 25

what are the two major congenital defects of the diaphragm?

Answer 25

• Failure of the diaphragm to completely close during development
• Herniation of the abdominal contents into the chest

Question 26

what is pulmonary hypoplasia?

Answer 26

the incomplete development of the lung

Question 27

where are the three most common places for a diaphragmatic hernia?

Answer 27

1. posteriolateral
2. anterior hernia
3. central hernia (in central tendon)

Question 28

what is a sliding hiatus hernia?

Answer 28

the stomach protrudes through the oesophageal hiatus pushing the oesophagus up

Question 29

what is a paraoesophageal hernia?

Answer 29

the stomach “rolls” up the oesophagus so it passes through the hiatus beside it