Proper digestion requires the coordinated effort of many hormones with various effects. how do gastrin, cholecystokinin (cck), and secretin influence digestion

The hormones involved in gastric regulation are released from the stomach and the small intestine. Gastrin has a stimulatory effect on parietal cells and chief cells and is released in the presence of partially digested peptides. The intestinal hormones, cholecystokinin and secretin, have inhibitory effects on parietal cells and chief cells. In addition, cholecystokinin release requires the presence of carbohydrates and lipids.