Final answer:
The secretions with buffers and mucus but few enzymes come from the duodenal glands in the submucosa of the duodenum and the mucus-secreting cells of the gastric glands, particularly in the pylorus region, and the stomach mucosa.
Step-by-step explanation:
The secretions with mostly buffers and mucus, but few enzymes, are produced by various specialized cells and glands within the gastrointestinal tract. One notable example is the submucosa of the duodenum, home to the mucus-secreting duodenal glands (Brunner's glands). These glands produce a bicarbonate-rich alkaline mucus that serves to buffer the acidic chyme as it enters the stomach. Another source of similar secretions is the gastric glands in the pylorus region and certain cells in the pyloric antrum, which produce mucus and various hormones. The stomach mucosa itself secretes a protective alkaline mucus layer. Compared to these secretions, the pancreas produces a different secretion: a pancreatic juice rich in enzymes and bicarbonate, which also helps to buffer the acidic gastric chyme in the small intestine.