Embryology

Question 1

What does the endoderm make (3)

Answer 1

Mucosa epithelium

Associated ducts and glands

Question 2

What does the visceral mesoderm make (4)

Answer 2

Lamina propria
Muscularis mucosa + Muscularis externa
CT of submucosa
External CT

Question 3

What do the ventral mesenteries make (2)

Answer 3

Lesser omentum

Falciform Ligament

Question 4

What do the dorsal mesenteries make (3)

Answer 4

Dorsal mesogastrium
Dorsal mesoduodenum
Dorsal mesocolon

Question 5

Endoderm subdivisions (3)

Answer 5

Foregut - Pharynx to proximal half of duodenum
Midgut - Distal half of duodenum to right 2/3 of transverse colon
Hindgut - Left 1/3 of transverse colon to rectum

Question 6

Organs in foregut have arterial supply from

Answer 6

Coeliac trunk

Question 7

Organs in midgut have arterial supply from

Answer 7

Superior mesenteric artery

Question 8

Organs in hindgut have arterial supply from

Answer 8

Inferior mesenteric artery

Question 9

Oesophagus formation (3)

Answer 9

Length increases rapidly at weeks 4-7
Circular muscle develops in week 5
Longitudinal muscle develops in week 8

Question 10

Stomach formation (2)

Answer 10

Starts at week 4 as fusiform dilation

Dorsal wall grows faster than ventral wall which forms greater curvature

Question 11

Stomach rotation (4)

Answer 11

Clockwise 90 degree along longitudinal axis
Anteroposterior axis location brings pyloris upwards and fundus downwards
Left vagus becomes anterior vagus trunk
Right vagus become posterior vagus trunk

Question 12

Mesenteries property and function

Answer 12

Continuous layer of serous membrane

Attaches gut tube to ventral and dorsal abdomen walls

Question 13

Omental Bursa formation (2)

Answer 13

Hollow space that is formed by the greater and lesser omentum posterior to stomach
Rapid growth of dorsal mesentery and stomach rotation around longitudinal axis

Question 14

Greater Omentum formation (2)

Answer 14

Dorsal mesentery continues to develop as double layered sac over small intestine and transverse colon
The layers fuse forming greater curvature of stomach

Question 15

Duodenum formation (3)

Answer 15

As stomach rotates duodenum moves from mid-line to right side of abdominal cavity
Dorsal mesentery fuses with peritoneum covering posterior abdominal wall
Duodenum and pancreas become retroperitonial

Question 16

Omphalocele (3)

Answer 16

Failure of intestinal loop to return into abdomen
Shiny sac at umbilical cord base
High mortality

Question 17

Gastroschisis

Answer 17

Protrusion of abdominal content through wall lateral to umbilical chord

Question 18

Pectinate line (2)

Answer 18

Below line is ectoderm

Above line is endoderm