GI Embryology 1 - GI system

Gastro-Embryology

Endoderm- forms mucosa of the gut

Surrounding lateral plate mesoderm differentiates into smooth muscle and
visceral peritoneum

Dorsal mesentery farmed by mesoderm fusing, this suspends the adult gut.
Embryonic gut at 28 days is attached to the yolk sac via the vitelline duct (or yolk
stalk).

Derivatives of primitive gut tubes



 Pharynx
o Pharyngeal pouches
 Foregut
o Larynx, trachea and lungs
o Pharynx and oesophagus
o Stomach and proximal part of the duodenum
o Pancreas
 Midgut
o Distal half of the duodenum
o Jejunum
o Caecum and appendix
o Ascending colon and 2/3 of transverse colon
 Hindgut
o Left 1/3 of transverse colon
o Descending colon
o Sigmoid colon
o Rectum and upper anal canal


Parasympathetic innervation relate to these divisions:
 Vagus nerve:
o Foregut
o Midgut
o Kidneys
 Pelvic nerve:
o Hindgut
o Bladder
o Reproductive organs

Sympathetic innervation:
 Coeliac ganglion: