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Title: How does each of the three phases of gastric secretion promote and facilitate gastric control? Post by: catgails on Aug 17, 2013 Need help with this question fast! Thanx!!
Title: How does each of the three phases of gastric secretion promote and facilitate gastric control? Post by: rmalviya on Aug 17, 2013 Phases of Gastric Secretion
Similarly to Salivary secretion, gastric secretion can be divided into three phases: Cephalic phase accounts for around 30% of the response to a meal controlled by the brain stimulated by senses - taste, smell, vision but also by thoughts. Vagal impulses releases ACh in main body of the stomach apart from directly stimulating secretion of acid it stimulates histamine release histamine stimulates release of gastrin from parietal G cells the three compounds initiate the cascade for production and release of HCl Gastric phase accounts for around 60% of the response involves both neural and humoral reflexes initiated by: distension of the stomach the presence of polypeptides in the antrum stimulate G cells to secrete gastrin low pH at antral mucosa inhibits gastric phase through the release of somatostatin from endocrine cells an important negative feedback regulation of gastric HCl secretion Intestinal phase accounts for less than 10% principle feedback via hormones from duodenum fats in the duodenum cause the release of Cholecystokinin (CCK) and Gastric Inhibitory Peptide (GIP) CCK stimulates chief cells to release pepsinogen GIP releases somatostatin- inhibits acid production secretin release from the duodenum also causes a release of stomatostatin acid in the duodenum acts by negative feedsback via intrinsic nerves |