apud cell atrophic gastritis autoantibody autoimmune disease bariatric surgery bile borborygmus cholecystokinin defecation delta cell duodenum enteric nervous system enterochromaffin-like cell enterochromaffin cell enterocyte enteroendocrine cell enterogastrone enterohepatic circulation entrez exocrine pancreatic insufficiency g cell gastric acid gastric chief cell gastric inhibitory polypeptide gastric juice gastrin gastrocolic reflex gastrointestinal physiology glycoprotein goblet cell haptoglobin histamine human physiology ileum interstitial cell of cajal intestinal juice k cell malabsorption medical subject headings medlineplus megaloblastic anemia migrating motor complex mucin mucoprotein mucus national center for biotechnology information orosomucoid pancreatic juice paneth cell parietal cell pepsin peptidoglycan peristalsis pernicious anemia phytohaemagglutinin portal venous system s cell saliva secretin segmentation contractions somatostatin stomach swallowing swiss-prot terminal ileum vomiting