The greatest amount of pancreatic exocrine secretion occurs when the acid chyme and food components in the duodenum stimulate the release of cholecystokinin and secretin from cells in the duodenal mucosa (intestinal phase of control). These two duodenal hormones also feed back to the stomach to decrease secretions and slow down the activity and emptying of the stomach until the duodenal chyme has been degraded by the enzymes and adjusted in pH by the pancreatic bicarbonate.