Final answer:
The digestive system is finely tuned by the brain and hormones. Neural responses to food include salivation and stomach acid production while hormonal controls, involving hormones like gastrin, regulate enzyme secretion and motility in the digestive tract.
Step-by-step explanation:
The operation of the digestive system is a complex process regulated by both neural and hormonal responses. When you smell, see, or think about food, an intricate response is triggered, starting with salivation and followed by the production of digestive juices. The brain is the central command center for these responses, including peristalsis, which moves food through the digestive tract. As the stomach stretches from food intake, neural pathways signal to your brain that you are full, promoting a feeling of satiety.
To manage digestion more specifically, hormones such as gastrin, secretin, cholecystokinin (CCK), and gastric inhibitory peptide are released, which regulate the secretion of gastric acid, enzymes, and bile, as well as control gastric emptying and motility. These hormones are secreted by endocrinocytes in the stomach's mucosal epithelium and the small intestine, initiating changes in the digestive organs' behavior, ultimately guiding the process of digestion from the moment food is perceived until it is fully digested.