Pancreatic secretions
Dr. Maria Gill
Assistant professor of physiology
MBBS, MPhil
Learning objectives
• Explain pancreatic exocrine and endocrine structure
• Enlist the composition of pancreatic juice
• Enlist the causes and effects of pancreatic insufficiency
• Explain the HCO3 secretion by acinar ductal cells
• Explain the regulation of pancreatic secretions
• Define pancreatitis
• Enlist the causes of pancreatitis and pancreatic insufficiency
• Explain the pathogenesis of acute pancreatitis
Acute pancreatitis
• A 55-year-old, morbidly obese, known diabetic
woman presented in emergency with vomiting,
fever and severe epigastric pain radiating to her
shoulder. She was taking Orlistat (Drug that
inhibit pancreatic lipase) for her obesity. She
had known history of cholelithiasis.
Ultrasonography of right upper quadrant
showed stone obstructing the pancreatic duct.
Her serum amylase and lipase were elevated. A
diagnosis of acute pancreatitis was made.
• a) Enlist the composition of pancreatic juice
• b) Explain how pancreas is protected from auto
digestion normally with the help of figure
• c) Explain in above scenario how gall stones
obstruction lead to pancreatic auto digestion
• d) Enlist the phases of pancreatic secretion and their
contribution output
Pancreas
• Lies parallel and behind the stomach
• Mixed glad (Exocrine and endocrine)
• Endocrine parts dispersed through
out the pancreas
• Exocrine part made up of grape like
clusters of secretory cells (acinar
cells) which open into ducts
• Acinar cells have well developed
RER and golgi apparatus (digestive
enzymes mainly)
• Pancreatic secretions open into
duodeneum
Exocrine pancreas
Exocrine pancreas secretions – Pancreatic juice
• Pancreatic enzymes actively
secreted by the acinar cells
• Pancreatic enzymes are
stored in zymogen granules
• Pancreatic ducts secrete
aqueous (watery) rich in
sodium bicarbonate
Composition of pancreatic juice
A. Enzymes
B. Bicarbonate rich solution
A. Pancreatic proteolytic enzymes
a. Duodenal enterpeptidase activates
trypsinogen
How pancreas is protected from
autodigestion?
Over whelmed trypsin inhibitior
leads to acute pancreatitis
b. Pancreatic amylase
Pancreatic amylase is
secreted in its active form
in pancreatic juice
c. Pancreatic lipase --- Only enzyme
that can digest fat
Secreted in an active form as triglycerides are not
the cell membrane component of pancreas
Pancreatic Insufficiency
How pancreatic insufficiency presents?
• Pancreatic enzyme deficiency results in serious maldigestion and
malabsorption of dietary fat
• Digestion of protein and carbohydrates is impaired to a lesser
degree because salivary, gastric, and small-intestinal enzymes
contribute
• Clinical manifestation is steatorrhea / excessive undigested fat in
the feces.
Think !
• A 4-year-old boy is brought to his pediatrician for an evaluation
because of failure to thrive and frequent diarrhea characterized by
pale, bulky, foul smelling stools. Diminished secretion of which
pancreatic product is most likely to be the primary cause of the
patients fat malabsorption?
• Lipase
• Procolipase
• Monitor peptide
• Cholecystokinin
• Bicarbonate
Pancreatic juice
b. HCO3 rich solution
Formation of iso osmotic HCO3 solution
• Aqueous NaHCO3 secretion
is by far the largest
component of pancreatic
secretion.
• 1 and 2 liters per day
Regulation of pancreatic secretion
a. Control of pancreatic secretions
b. Phases of pancreatic secretions
a. Control of pancreatic secretions
Multiplicative effect of different stimuli
• Different stimuli of pancreatic secretion occur at once,
the total secretion is far greater than the sum of the
secretions caused by each one separately.
• Various stimuli are said to “multiply,” or “potentiate,”
one another.
Hormonal regulation of pancreatic secretion
Hormonal regulation of pancreatic secretion
Regulation of pancreatic secretion
Comparison of pancreatic secretion
Summary
