Secretion of digestive glands Main functions of digestive fluids Gastrointestinal innervation Intrinsic (or enteric)nervous system Submucosal myenteric plexus Extrinsic nervous system Parasympathetic sympathetic nerves Gastrointestinal hormones General functions Brain-gut peptides• Secretion of digestive glands * Main functions of digestive fluids • Gastrointestinal innervation * Intrinsic (or enteric) nervous system Submucosal & myenteric plexus * Extrinsic nervous system Parasympathetic & sympathetic nerves • Gastrointestinal hormones * General functions * Brain-gut peptides