PHRM 311 Lecture Notes - Microvillus, Gallstone, Amylase
Document Summary
Anatomy and physiology of the gi system (part 3) Provides enzymes and adjusts ph to permit digestive activity. Gastric acid contacting duodenal mucosa (s cells) releases secretin (stimulates release of water and bicarbonate) in response to lowered ph. Low ph, fatty acids and essential amino acids promote release of cholecystokinin (cck) from duodenal and proximal jejunal mucosa (ito or i-cells) to release enzymes. Elevated ph and lowered cck turn off release of bicarbonate and digestive enzymes. Amylolytic enzymes (e. g. amylase) break down starches. Lipolytic enzymes (e. g. lipase) break down lipids. Proteolytic enzymes (e. g trypsin, chymotrypsin) break down proteins. Mutation leads to an abnormal cystic fibrosis transmembrane conductance. Ducts are unable to secrete bicarbonate and water, so enzymes are not flushed out of the pancreas into the duodenum. Lack of bicarbonate failure to neutralize gastric acid inactivation of enzymes that make it into the duodenum. Can result in destruction of exocrine pancreas during fetal development.
