The activities of the gastro-intestinal tract are under both neural and hormonal control. The gastro-intestinal tract is innervated by intrinsic nerves as well as by extrinsic nerves. The sight, smell and/ or the presence of food in the oral cavity can stimulate the secretion of saliva. Neural signals stimulate the gastric and intestinal secretions. The muscular activities of different parts of the alimentary canal can also be moderated by neural mechanisms, both local and through CNS. Hormonal. Control of the secretion of digestive juices is carried out by the local hormones produced by the gastric and intestinal mucosa such as gastrin, cholecystokinin and secretin etc.