Pancreatic exocrine function Flashcards
What are the two functions of the pancreas?
- Endocrine secretion
- Exocrine secretion
(aqueous bicarbonate secretion + enzyme secretion)
What is the pancreatic duct?
Runs along the inside of the pancreas and is very thin 1-4mm thick as it goes from tail to body
How much bicarbonate do we secrete a day?
1 L/day
Where is HCO3- produced ?
Epithelial cells in the pancreatic duct produces HCO3- and H2O
Why is bicarbonate secreted?
- This secretion protects duodenal mucosa by neutralising stomach acid
- Buffers duodenal contents to optimise pH for enzyme digestion
What initiates protein digestion?
Pepsin in the stomach
Where does the majority of protein digestion occur?
In the small intestine
What are some pancreatic proteases and how are they stored?
- Trypsin
- Chymotrypsinogen
They are stored as trypsinogen and chymotrypsinogen
How are pancreatic proteases activated?
- Trypsinogen activated by enterokinase
- Trypsin activates chymotrypsinogen and additional trypsinogen
What do lipases hydrolyse and what aids this?
Triglycerides to monoglycerides and free fatty acids
- Bile salts helps aid this
What is orlistat?
It is a pancreatic lipase inhibitor so stops some of the fat you eat from being absorbed. So it is used with weight loss
What does amylase do?
- Hydrolyses starch to maltose (glucose- glucose disaccharide) and maltotriose (trisaccharide) and limit dextrins (low molecule carbohydrate made from starch)
Where is amylase found?
- Salivary amylase has a small role
- But most is found and secreted by pancreas
What is the cephalic stage of enzyme secretion?
This is the low level stimulus of anticipating a meal. Sight, smell etc…
Occurs through vagal innervation and release of gastrin
What is the intestinal stage of enzyme secretion?
Secretin, Cholecystokinin, Gastrin are all secreted
What does Cholecystokinin (CCK) do?
It is a pancreatic enzyme which delays gastric emptying. It does this by inhibiting the gastric acid secretion when the gallbladder contracts
How does pancreatic secretion reduce?
As proteins and fats are digested and absorbed, pH rises and stimuli for CCK and secretin disappear and so pancreatic secretion falls as there is no stimulus
What 2 hormones are vital for carbohydrate and lipid metabolism?
Inuline an glucagon
What are some consequences of pancreatic exocrine insufficiency?
Malnutrition
Osteoporosis
Increased cardiovascular morbiditiy
Symptom burden
How do we assess for poor pancreatic function?
History, risk factors
Imaging
Faecal elastase
Markers of malnutrition
How do you treat PEI (pancreatic exocrine insufficiency)
Pancreatic enzyme replacement therapy
STOP smoking
Bone health assessment
Treat the underlying cause
