Pancreatic secretion Flashcards
What substances do acini produce
Lipases, proteases and amylases
What structure are prancreatic enzymes contained in
zymogen granules
What are the centroacinar cells
the cells of the intercalated
ducts that extend partially into the lumen of pancreatic acini
What is the name of the region where the main pancreatic enters the duodenum
ampulla of Vater
Which portions of the pancreatic duct forms the main pancreatic duct
dorsal and ventral pancreatic ducts
Where do the ventral and dorsal pancreatic ducts join to form the main pancreatic duct
The head of the pancreas
Which nerves stimulate pancreatic secretion
Cholinergic nerves
Food in the stomach stimulates stretch receptors which stimulates pancreatic secretion by which reflex
Vasovagal reflex
Most of the pancreatic secretion is controlled by..
Secretin and CCK
Function of trypsin inhibitors
Prevents activation of proteases in the pancreas
What happens if trypsin is activated in the pancreatic cells
Pancreatitis
Function of pancreatic amylase
Hydrolyze a-1,4-glucoside linkage of complex carbohydrates into maltose, maltotriose and alpha limit dextrin
Which carbohydrate cannot be broken down by pancreatic amylase
B linkages of cellulose
Another name for sterol lipase
Cholesterol esterase
Products that pancreatic lipase produce
2 fatty acids and a monoglyeride
What is necessary for pancreatic lipase to be effective
Colipase
Function of colipase
Removes bile salts from micelles so pancreatic lipase can bind to them
Function of cholesterol esterase
Break down cholesterol esters into cholesterol and fatty acids
Inactive zymogens that pancreatic proteases are secreted as
Trypsinogen, chymotrypsinogen and procarboxypeptidase
Active form of trypsinogen
Trypsin (endopeptidase)
Active form of chymotrypsinogen
Chymotrypsin (endopeptidase)
Procarboxypeptidase
Carboxypeptidase (exopeptidase)
What activates trypsinogen
Enterokinase
What activates chymotrypsinogen
Trypsin
What activates procarboxypeptidase
Trypsin
What organ secretes enterokinase
Lining of small intestine
Reason for isotonic fluid in pancreas
High permeability of the duct to water
Function of the Cystic Fibrosis Transmembrane Conductance Regulator (CFRT)
A chloride channel that allow Cl- to enter lumen and bring water with it
What activates CFRT
cAMP
What happens in Cystic Fibrosis
Mutation on chromosome 7 of the CFTR gene causing the Cl- to not go into the lumen and bring water, leading to very viscous mucus
What is exchanged for Cl- when it enter the lumen
Bicarbonate ions
How does secretin lead to secretion of bicarbonate
Secretn activates Gs—cAMP which activates CFTR leading to secretion of chloride then exchange with bicarbonate
Secretin is released in response to
acid in the duodenum
CCK is released in response to
Proteins and amino acids
CCK results in release of
enzymes such as proteases, lipases and amylases
Which neurotransmitter also causes release of secretin and CCK
Acetylcholine (from parasympathetics- vagus nerve)
Which drug can inhibit acetylcholine release on acinus and duct cells
Atropine or parasympathetic inhibitors
