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 Digestive biscuit A digestive biscuit, sometimes described as a sweet-meal biscuit, is a semi-sweet biscuit that originated in Scotland, and is popular worldwide. The digestive was first developed in 1839 by two Scottish doctors to aid digestion. The term "digestive" is derived from the belief that they had antacid properties due to the use of sodium bicarbonate when they were first developed. Historically, some producers used diastatic malt extract to "digest" some of the starch that existed in flour prior to baking. First manufactured in 1892, McVitie's digestive is the best-selling biscuit in the UK. A prominent feature in British