Lower GI II Flashcards
What is the role of amylase?
hydrolyze starches to form sugars.
starch—-> disaccharides
Where are disaccharides broken down into monosaccharides?
brush border of the small intestine and monosaccharides are absorbed by enterocytes
Describe the sequential breakdown of proteins into amino acids; where do each of the steps occur?
Where does lipid digestion begin. What enzymes are involved? what role do micelles and chylomicrons play?
For cholecystokinin, secretin, and gastrin, give the site of secretion, targets, and effects.
What organ produces bile salts?
the liver (not the gall bladder)
Where does lipid digestion begin?
in the small intestine.
Lipids enter as triglyceride droplets.
What is the function of pancreatic lipase?
emulsify large lipid droplets into smaller droplets and release fatty acids and glycerol
What molecules can micelles transport?
fatty acids, monoglycerides, glycerol, phospholipids, cholesterol and vitamin K and A.
What cells of the small intestine absorbs the micelles?
apical plasma membrane of enterocytes in the small intestine and requires fatty acid binding proteins (FABPs)
Where does carbohydrate digestion begin?
in the mouth
What secretes cholecystokinin?
upper intestinal mucosa (duodenum)
A response to what initiates cholecystokinin secretion?
secreted in response to gastric contents
What are the 4 actions of cholecystokinin?
1) pyloric sphincter to slow down emptying of stomach
2) stimulates bile release from gall bladder
3) stimulates secretion of pancreatic enzymes
4) competitive inhibitor of gastrins\
What secretes secretin?
epithelial cells of duodenum
