Development of the digestive system Development of the digestive system The development of the digestive system concerns the epithelium of the digestive system and the parenchyma of its derivatives, which originate from the endoderm. Connective tissue, muscular components, and peritoneal components originate in the mesoderm. Different regions of the gut tube such as the esophagus, stomach, duodenum, etc. are specified by a retinoic acid gradient that causes transcription factors unique to each region to be expressed. Differentiation of the gut and its derivatives depends upon reciprocal interactions between the gut endoderm and its surrounding mesoderm. Hox genes in the mesoderm are induced by a Hedgehog
Digestive system of gastropods Digestive system of gastropods The digestive system of gastropods (slugs and snails of every kind) has evolved to suit almost every kind of diet and feeding behavior. Gastropods as the largest taxonomic class of the mollusca are very diverse indeed: the group includes carnivores, herbivores, scavengers, filter feeders, and even parasites. In particular, the radula is often highly adapted to the specific diet of the various group of gastropods. Another distinctive feature of the digestive tract is that, along with the rest of the visceral mass, it has undergone torsion, twisting around through 180 degrees during the larval stage, so