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 culture, the digestive is ranked the fourth most popular biscuit for "dunking" into tea, with the chocolate digestive coming in at number one. In 1839, digestives were first developed in the United Kingdom by two Scottish doctors to aid digestion. Digestives featured in advertisements for the Berkshire-based biscuit company Huntley & Palmers in 1876, with a recipe being given in Cassell's "New Universal Cookery Book" of 1894. In 1851 an issue of The Lancet London's advertising section offered "brown meal" digestive biscuits. At the time, it was asserted grain millers knew only of bran and endosperm. After 10% of the