Embryology 3

Question 1

what does the tubular outgrowth from foregut (oesophagus) develop into?

Answer 1

the trachea and lung buds

Question 2

what happens when the lung buds proliferate?

Answer 2

they will invaginate laterally into the pleural cavities, so forming visceral and parietal pleura and the pleural cavity

Question 3

how is the diaphragm formed

Answer 3

whilst the parts of the trachea and lungs are forming a transverse septal ‘shelf’ develops between thorax and abdomen below the pleural cavities

Question 4

what is the septal ‘shelf’ composed of

Answer 4

4 components that fuse to form the diaphragm

Question 5

how do congenital abnormalities come about?

Answer 5

things can go wrong with the embryonic tracheal, lung and diaphragmatic formation

Question 6

what does folding of the embyro during week 3 give rise to?

Answer 6

the primitive gut tube

Question 7

what comes from the midgut and hindgut

Answer 7

gut

Question 8

what comes from the ventral wall of the foregut

Answer 8

trachea and lungs

Question 9

when does tracheal and lung development start

Answer 9

4 weeks gestation

Question 10

how does the trachea start to develop

Answer 10

a median outgrowth called the laryngotracheal groove from the ventral part of the foregut

Question 11

how do the trachea and oesophegus separate

Answer 11

oesophagotracheal septum - that completely separates them into trachea ventrally and oesophagus dorsally - a relationship that is maintained into adulthood.

Question 12

what is Tracheoesophageal fistula

Answer 12

A fistula is an abnormal connection or passageway that connects two organs or vessels that do not usually connect
TOF is a common congenital abnormality.

Question 13

Define atresia

Answer 13

a condition in which a passage in

the body is closed or absent (abnormal to usual anatomy)

Question 14

lining of the thoracic wall

Answer 14

becomes lined by a layer ofparietal pleura, derived from somatic mesoderm

Question 15

what is the gap between the parietal and visceral pleurae called

Answer 15

called pleuroperitoneal canals - these eventually become the pleural canals

Question 16

during lung development, when are the alveolar sacs formed?

Answer 16

during 27-40 week period

alveolar sacs will be progressively divided into smaller subunits leading to the formation of alveoli later on

Question 17

what is respiratory distress syndrome (RDS)

Answer 17

• acute lung disease caused by surfactant deficiency, which leads to alveolar collapse and noncompliant lungs (underdeveloped lungs basically)
• Affects 2 % of neonates

Question 18

what does the septum transversum become in the diagphragm

Answer 18

the central tendon

Question 19

what do the pleuroperitoneal membranes become

Answer 19

the primitive diaphragm

Question 20

what does the dorsal mesentery of oesophagus become

Answer 20

the median portion and crura (leg shaped tendons) of the diaphragm

Question 21

which embryonic components make up the peripheral parts of diaphragm

Answer 21

muscular ingrowth from lateral body walls

Question 22

what 4 embryonic components develop into the diaphragm

Answer 22

Septum transversum Pleuroperitoneal membranes
Dorsal mesentery of oesophagus
Muscular ingrowth from lateral body walls

Question 23

where is the septum transversum initially located?

Answer 23

opposite C3-C5 somites

it migrates caudally

Question 24

3 major congenital defects during diaphragm development

Answer 24

Failure of the diaphragm to completely close during development

Herniation of the abdominal contents into the chest

Pulmonary hypoplasia

Question 25

define hernia

Answer 25

bulge or protrusion of an organ through the structure or muscle that usually contains it.

Question 26

what 3 types of diaphragmatic herniae can you get?

Answer 26

1. posteriolateral (Bochdalek) hernia
2. anterior (Morgagni) hernia
3. central hernia

Question 27

what 2 types of hiatal herniae can you get

Answer 27

a hernia through the holes in the diaphragm

1. sliding hiatus hernia
2. paraesophageal hiatus hernia ‘rolling’ hiatus hernia