Digestion of Carbohydrates and Proteins Flashcards
What is the functional unit of the exocrine pancreas made up of?
an acinus and its draining ductule
What does the exocrine pancreas contain?
- enzymes (acinus)
- electrolytes (ductule)
- mucin (goblet)
What does the endocrine pancreas produce?
- insulin
- glucagon
- somatostatin
- pancreatic polypeptide
What do acinar cells in the pancreas secrete?
peptidases, lipases, alpha-amylases and nucleases
What do ductal cells secrete?
1.2-1.5L/day of pancreatic juice
Why does pancreatic juice have a high HCO3- concentration?
to regulate the pH of the upper intestine
What can failure to produce pancreatic juice lead to?
duodenal ulcers
What does the aqueous component of pancreatic juice contain?
- same amount of sodium and potassium as the ECF
- more HCO3- than ECF
How is an acid tide formed in the plasma?
the HCO3- concentration increases as the rate of secretion increases so there is less time for HCO3-/Cl- exchange
What are the 3 enzymatic components of the pancreatic juice?
- pancreatic α-amylase
- pancreatic lipases secreted in their active forms
- pancreatic proteases secreted in inactive zymogen forms
What does pancreatic α-amylase do?
- hydrolyse glycogen and starch
- complex carbohydrates (except cellulose) into disaccharides
Give examples of pancreatic proteases
trypsin, chymotrypsin and carboxypeptidase A and B
What do water-insoluble esters require?
bile salts
What is pancreatic secretion stimulated and inhibited by respectively?
- stimulated by parasympathetic system
- inhibited by sympathetic system
What is the cephalic phase of pancreatic secretion activated and enhanced by?
activated by thought, sight, smell or taste of food and enhanced by vagal stimulation
What happens in the cephalic phase?
secretion of pancreatic juice