Bowel development

Front intestine

 * From the oropharyngeal membrane below the outlet of the liver and pancreas,
 * epithelium and glands - endoderm of the yolk sac,
 * muscles - ectomesenchym of pharyngeal arches, splanchnic (lateral) mesoderm,
 * sublingual and submandibular salivary gland, esophagus, stomach, part of duodenum, liver, gallbladder, pancreas.

Middle intestine

 * reaches the Cannon-Boehm point (in the area of flexura lienalis = flexura coli sinistra),
 * part of the duodenum, jejunum, ileum, caecum, ascending and most of the transverse colon.

Hind intestine

 * Terminated by a cloacal membrane (linea dentata canalis analis),
 * descending colon, rectum.

Structures attaching the primitive intestine

 * Ventral mesogastrium (disappears for middle and hindgut)

-> omentum minus a ligamentum falciforme hepatis - boundaries of the bursa omentalis.


 * Dorsal mesogastrium (complete, allow rotation of organs in the peritoneal cavity) -> omentum majus, mesenterium, mesoappendix, mesocolon transversum, mesocolon sigmoideum, Treitz retropancreatic membrane.

Three body cavities
The coelom cavity is gradually divided into:


 * pericardial cavity (pericardial),


 * pleural cavity,


 * peritoneal cavity.