Liver & Pancreatic Secretions in Digestion Flashcards
What hormone regulates gall bladder contraction?
CCK
What is the result of absence of bile?
steathorrhea
What are the components of bile?
water, bile pigments (bilirubin), bile salts, fatty acid, cholesterol, lecithin (emulsifier), inorganic salts
What component of bile causes gall stones?
cholesterol
What are bile salts derived from?
cholesterol
What is the structure of bile salts?
steroid structures with a carboxylic acid group that is commonly an amide linked to glycine or taurine to increase solubility
What is the function of bile acids?
they are detergents
Why does fat digestion require emulsifying action?
so that the enzymes can gain access
What enzymes are needed in fat digestion?
lipase and colipase
What is the purpose of enterohepatic circulation?
To reabsorb bile salts in the ileum so they can be reused
What makes up pancreatic secretions?
bicarbonate from duct cells and enzymes from acinar cells
What stimulates release of contents from exocrine pancreatic cells?
acetylcholine, CCK or secretin
Where is CCK produced?
in the duodenum
What are the actions of CCK?
gall bladder contraction, digestive enzyme release from pancreas, release of insulin and contributes to the feeling of fullness
What are zymogens?
Inactive enzymes
What activates zymogens?
other enzymes
What is the action of trypsin inhibitor?
Exists in the pancreas to inhibit any trypsin that is accidentally activated to prevent digestion of the pancreas
What activates trypsin?
enteropeptidase from intestinal enterocytes
What enzymes does trypsin activate?
chymotrypsin, elastase, carboxypeptidase, colipase
What activates lipase?
colipase
What gives the substrate specificity of serine proteases?
the properties of the S1 sub site adjacent to serine
What are the two main causes of pancreatitis?
alcohol abuse and gall stones
What is the most energy expensive nutrient?
protein - requires lots of transporters
What is orlistat?
A lipase inhibitor
How does margarine lower cholesterol reabsorption?
the phytosteroids block the receptors for reuptake of cholesterol in the terminal ileum
