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
Acidic oxide increase the hydrogen ion concentration of water. For instance, carbon dioxide increases the hydrogen ion concentration of rain water (pH = 5.6) by a factor of 25 compared to pure water (pH = 7). They are also Lewis acids, because they accept electron pairs from some Lewis bases, most notably base anhydrides. The oxides of period three elements demonstrate periodicity with respect to acidity. As you move across the period, the oxides become more acidic. Sodium and magnesium oxides are alkaline. Aluminium oxides are amphoteric (reacting both as a base or acid). Silicon, phosphorus, sulfur, and chlorine oxides are acidic.