Respiratory embryology

Question 1

What is laryngotracheal groove and when does it start developing?

Answer 1

It is median tubular outgrowth from ventral wall of foregut -diverticulum that will develop into trachea and lung buds. It starts developing at week 4

Question 2

What happens to proliferating bud?

Answer 2

Proliferating bud invaginate both pleural cavities laterally forming visceral and parietal pleura

Question 3

How does trachea and oesophagus separate?

Answer 3

By tracheoespphageal septum that separates trachea and oesophagus ventrally and dorsally, trachea is anterior and oesophagus is posterior

Question 4

What is treacheoesophageal fistula?

Answer 4

Passage between the two

Question 5

What is oesophageal atresia?

Answer 5

Blind ended oesophagus, oesophagus ends and does not connect to loweroesophagus and stomach

Question 6

What is transverse septal shelf?

Answer 6

Shelf that develops between the thorax and abdomen, separates two cavities

Question 7

What are the 4 components of the diaphragm?

Answer 7

septum transversum, pleuroperitoneal membranes, peripheral body wall muscle, mesentery of oesophagus

Question 8

What forms from septum transversum ?

Answer 8

tedious part of diaphragm, initially located opposite C3 to C5 somites, migrates caudally and takes all its innervation with it

Question 9

What forms form 2 pleuroperitoneal membranes ?

Answer 9

muscular part of diaphragm

Question 10

What is formed from peripheral body wall muscle ?

Answer 10

Muscular part, peripheral parts of the diaphragm, those that are innervated by intercostal nerves

Question 11

What is formed from mesentery of oesophagus ?

Answer 11

Crura of diaphragm

Question 12

Name the stages in the differentiation of the lung bud

Answer 12

Embryonic, pseudoglandular, canalicular, saccular and alveolar

Question 13

What happens during the embryonic development ?

Answer 13

respiratory diverticulum appear around day 26 from the ventral part of foregut, it then develops to trace and two lateral pockets, simultaneously vascular connections develop, pulmonary arteries

Question 14

What happends during foetal period?

Answer 14

pseudoglandular, canalicular, saccular stage

Question 15

What happens in speudoglandular stage?

Answer 15

pulmonary structures are set up except elements needed for gas exchange, initial proliferation into glands

Question 16

What happens in canalicular stage?

Answer 16

terminal bronchioles give rise to tubules that makes the respiratory portion, differentiation of epithelium into cuboidal security cells type II pneumocytes and flat cells type I pneumocytes

Question 17

What happens during saccular stage?

Answer 17

Formation of alveolar sacks by primary septum progressive divided into smaller units

Question 18

What happens in alveolar stage?

Answer 18

This is post natal stage, formation of alveoli form terminal sacs, they enlarge, by the age of 8 years the number of alveoli reaches adult number

Question 19

What are the possible congenital malformations of respiratory system?

Answer 19

Respiratory distress syndrome, accessory lobes, agenesis of lungs, lobe of azygous vien, pulmonary hypoplasia, hiatal hernias, diaphragmatic hernias