Digestive Endocrinology and Glucose Metabolism Flashcards
What is the anatomical location of the pancreas?
retroperitoneal, 2nd lumbar verterbral level. Head lies in the duodenum and tail lies in the spleen
What are the functions of the endocrine and exocrine cells of the pancreas?
exocrine: acinar cells secrete pancreatic enzymes into pancreatic duct. endocrine: Islet of Langerhans cells secrete hormones into blood vessels
What is the function of alpha cells?
releases glucagon increasing blood glucose thru breakdown of glycogen, gluconeogenesis, transport AA into liver and converts to glucose, and activates adipose lipase
What stimulates alpha cells to release glucagon?
low glucose levels, high concentrations of AA, or strenuous excercise
What is the function of beta cells?
produce insulin which decreases blood glucose by increased uptake in cells, glycogenosis, prevent fat breakdown, increased protein synthesis, increased triglyceride synthesis,
What is the major regulator of insulin?
glucose. In pancreatic beta cell, glucose transporters allow influx of glucose: glucokinase. Results in closure of K+ channels and opening of Ca+ channels allowing secretion of insulin by exocytosis
What happens with intake of carbs?
secretion of insulin causes uptake and storage of glucose. If not used in muscle it’s stored as glycogen in the liver. Once it has stored all the glycogen it can, insulin promotes conversion of glucose to fatty acids.
What is the effect of insulin on fat metabolism?
insulin activates lipoprotein lipase which splits the triglycerides into fatty acids again for them to be absorbed into the adipose cells
What is the effect of insulin on AAs?
Stimulates transport of many AA into the cells. Inhibits the catabolism of proteins especially in muscle cells.
What is the function of delta cells?
secretes somatostatin which inhibits secretion of GH, thyrotropin, insulin, glucagon, gastrin, gastric acid secretion, and exocrine secretion of pancreas
What cells are responsible for fluid and electrolyte secretion by the pancreas?
centroacinar cells
Describe the flow of the ductular system of the pancreas
acinus–>small intercalated ducts–>interlobular duct–>pancreatic duct
What activates the pancreatic digestive enzymes?
In the intestinal lumen glycoprotein peptidase activates trypsinogen then trypsin activates the other inactive proenzymes
How do pancreatic secretions affect pH of the small intestine?
Sodium bicarbonate is secreted by small ductules from the acini. The ductule cells are stimulated by secretin released when acidic chyme enters the small inestine. water and bicarb makes the small intestine more alkaline so the pancreatic enzymes work better
What factors regulate pancreatic secretion?
acetylcholine from vagal nerve increase secretions, secretin stimulates release of H2O/bicarb, CCK stimulates greater enzyme release, and trypsin inhibitor prevents activation of trypsinogen
