Gastric Phase of Digesting a MealSlide 2The Major Regions of the StomachStructure of Gastric MucosaSlide 5Activation of the pepsinogens to pepsinsThe Parietal Cell: Inactive (A), Active (B)Slide 8Feedback regulation of gastric acid secretion by somatostatinSlide 10Mechanism of H+ and Cl- secretion by the parietal cell.Slide 12Regulation of gastric acid secretionSecretagogues and signal transduction in the parietal cellSlide 15Mucus layer serves as a diffusion barrier.Slide 17Gastric EmptyingIntestinal Phase of Gastric SecretionGastric Phase of Digesting a MealFigure 21-2b•Orad region•Thin walled•Receptive Relaxation•Caudad region•Thick walled•Mixing with strong contractions•Propulsion through Pyloric sphincterThe Major Regions of the StomachStructure of Gastric MucosaNeural regulation of gastric acid secretion in the gastric phaseActivation of the pepsinogens to pepsinsThe Parietal Cell: Inactive (A), Active (B)The parietal cell is regulated by neural, hormonal, and paracrine pathways.Feedback regulation of gastric acid secretion by somatostatinParasympathetic stimulation of gastric secretions via enteric neuronsMechanism of H+ and Cl- secretion by the parietal cell.The direct and indirect actions of the three acid secretagogues.Regulation of gastric acid secretionSecretagogues and signal transduction in the parietal cellThe secretion of mucus by the gastric mucosa is an important protective mechanism.Mucus layer serves as a diffusion barrier.Gastric Emptying•The stomach contains about 1 liter, composed of solids, liquids, and gastric secretions.•Liquids empty more rapidly than solids; isotonic content faster than hypo- or hypertonic content.•Solids reduced to < 1mm3•Rate slowed by fat content and presence of H+ in duodenumIntestinal Phase of Gastric