Development of the respiratory System

Question 1

What do the spaces in the lateral plate mesoderm become?

Answer 1

The intraembryonic coelom

Question 2

What does the primitive yolk sac give rise to?

Answer 2

• The gut tube
• The secondary yolk sac
• The viteline duct

Question 3

What does the intaembryonic coelom become?

Answer 3

The body cavities

Question 4

What does the somatic mesoderm line?

Answer 4

The wall of the thoracic cavity

Question 5

What does the gut tube give rise to?

Answer 5

• Digestive system
• Accessory organs of digestive system
• Respiratory system

Question 6

What is the gut tube formed from?

Answer 6

The endoderm

Question 7

What is the respiratory diverticulum?

Answer 7

Develops from gut tube and grows anteriorly towards visceral layer of lateral plate mesoderm and also inferiorly
Develops into respiratory tract

Question 8

What does the tracheo-esophageal ridge do?

Answer 8

Seperates the gut tube into foregut and respiratory diverticulum

Question 9

Where/when do the laryngeal arches appear?

Answer 9

Cervical part of gut tube around week 4

Question 10

How many pharyngeal arches are there?

Answer 10

5

Question 11

What does each pharyngeal arch have?

Answer 11

• A cartiliginous element (develops into bone, ligament or cartilage)
• Aortic arch artery
• Its own nerve

Question 12

What are the two swellings in the laryngeal orifice?

Answer 12

Epiglottal and laryngeal

Question 13

What isthe small oriffice called that makes a connection between foregut and respiratory tract?

Answer 13

Laryngeal orifice

Question 14

What does the endoderm develop into (in the respiratory system)?

Answer 14

Respiratory epithelium only

Question 15

What does the mesoderm develop into (in the respiratory system)?

Answer 15

Cartilage, trachealis muscle etc.

Question 16

What structures does the diaphragm develop from?

Answer 16

4 structures

• Pleuroperitoneal fold (posterolateral part of intraembryonic coelom)
• Septum transversum (anterior foetal wall)
• Mesentery of gut tube
• Abdominal muscle walls ingrow

Question 17

What is the crus of the diaphragm developed from?

Answer 17

The mesentery

Question 18

What happens if one of the structures which develop the diaphragm does not meet?

Answer 18

Diaphragmatic hernia occurs

Question 19

What does the pleuropericardial fold contain?

Answer 19

Myoblasts from C3, 4, 5

Phrenic nerve

Question 20

What is the most common congenital respiratory disorder

Answer 20

• Defect with tracheo-oesophageal ridge
• Gut tube becomes disconnected
• Proximal part of gut tube becomes atresic
• Distal part maintains connection with respiratory system
• 90% of disorders

Question 21

What is the abnormal connection between the trachea and oesophagus called (congenital defect)?

Answer 21

Tracheoesophageal fistula (can cause pneumonitis from stomach acids)

Question 22

What are the diaphragmatic hernias

Answer 22

• Bochdalek hernia
  Posterolateral defect in fusion of pleuro-peritoneal folds
  Most common
  95%
• Morgagni hernia (anterior, 2%)
• Central hernia (defect of septum transversum)