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 biscuit in some varieties. A digestive biscuit averages around 70 calories, although this sometimes varies according to the factors involved in its production. Digestive biscuits are frequently eaten with tea or coffee. Sometimes, the biscuit is dunked into the tea and eaten quickly due to the biscuit's tendency to disintegrate when wet. Digestive biscuits are one of the top 10 biscuits in the United Kingdom for dunking in tea. The digestive biscuit is also used as a cracker with cheeses, and is often included in "cracker selection" packets. In the UK, McVitie's digestive is the best selling biscuit, with 80 million