Pancreas Flashcards
How is pancreatic enzymes transported into lumen without damaging pancreas/how is pancreatic secretion controlled?
Pancreas creates strong enzymes eg protease in large quantities. This would break down the pancreatic cells if the enzymes were active.Therefore pancreases sends inactive enzymes to the duodenum. These are called inactive zymogensThis prevents autodigestion of the pancrea due to proteaseCells in the small intestines are coated in enterokinase on the villi (brush border)The enterokinase activates trypsinogen and convert it into trypsin Trypsin will activate all other protease
How is bicarbonate created/secreted into lumen and how is alkaline tide neutralised?
HCO3- is created in ductal cells Secretin stimulates the ductal cell causing CO2 to diffuse into the ductal cell. The CO2 combines with H2O to create H2CO3 which breaks up into H+ and HCO3- .( the lumen is currently acidic and blood is alkaline)H+ is pumped into the blood to neutralise HCO3- (alkaline tide)HCO3- and CL- are exchanged to pump HCO3- into the lumen to neutralise the acid (CFTR also pumps HCO3- into lumen)- cystic fibrosis channel so patients with this disease can move HCO3- and Cl- into lumen (water also will not follow) so the patients will struggle to get digestive enzymes through duct into duodenum so they have a problem digesting food.
What are ductal cells and what do they do in the pancreas?
Pancreatic juice created at acinar cells passes through ductal cells where Na+/Cl- are removed and HCO3-/K= are added. No movement of water.
What are acinar cells and what do they do in the pancreas?
Produce large quantities of digestive enzymes. Ion from near-by Blood vessel diffuse into acinar cells causing water to enter acinar cells from blood plasma by osmosis to create pancreatic juice. Acinar cells then add digestive enzymes to the pancreatic juice. Acinar cells are mainly stimulated by CCK.
What is secreted from the pancreas and what does this do?
Pancreatic juice contains 90% protease, 7% amalase, 2% lipase and ,1% nuclease (break down DNA and RNA). The pancreases also creates and releases insulin from islets of Langerhans and releases it into the blood stream. HCO3- is produced in the pancreas and is secreted with the pancreatic enzymes it is used to neutralise acid in the lumen.
How is the pancreas stimulated?
Acidic chyme enters the duodenum. Inside the duodenum there a specialised cells which are sensitive to acid and detects there is food present in the duodenum , this causes the endocrine cells of the duodenum to release secretin from I cells( fatty acids and proteins would cause the release of CCK-cholecystokinin from s cells). CCK also stops acid production and stimulates contaction of gall bladder and release of biHow is the pancreases stimulated?
Food from the stomach/chyme enters the duodenum. Inside the duodenum there are specialised cells which are sensitive
CCK and secretin are secreted into the blood and travel to the pancreasAt the pancreas CCK stimulates the release of pancreatic enzymes containing juice (from acinar cells) and secretin causes the release of HCO3- into the duodenum (from ductal cells).During cephalic and gastric phase stimulation of the vagus nerve causes release of pancreatic juices
How is the pancreas stimulated?
Acidic chyme enters the duodenum. Inside the duodenum there a specialised cells which are sensitive to acid and detects there is food present in the duodenum , this causes the endocrine cells of the duodenum to release secretin from I cells( fatty acids and proteins would cause the release of CCK-cholecystokinin from s cells). CCK also stops acid production and stimulates contaction of gall bladder and release of biHow is the pancreases stimulated?
Food from the stomach/chyme enters the duodenum. Inside the duodenum there are specialised cells which are sensitive
CCK and secretin are secreted into the blood and travel to the pancreasAt the pancreas CCK stimulates the release of pancreatic enzymes containing juice (from acinar cells) and secretin causes the release of HCO3- into the duodenum (from ductal cells).During cephalic and gastric phase stimulation of the vagus nerve causes release of pancreatic juices
Can the pancreases function if damaged?
The pancreas CAN function if it is damaged as it has huge functional reserve foR endocrine activity
What is the function of the pancreas?
Produce and release pancreatic juices (which contain digestive enzymes into the lumen) into the duodenum to aid digestion and also produces and releases HCO3- into the duodenum to neutralise acid that was transported with the food (this is an exocrine function). The secretions are released into the duodenum through the ampulla of vater ( also where bile enters from). The pancreas also produces insulin (endocrine function). 99% of cells in pancreases are exocrine cells and 1% are endocrine cells (islets of Langerhans) which produce insulin/hormone and release it into the blood .
