17: Digestion And Absorption Flashcards
Three primary sugars in the human diet
- Sucrose
- Lactose
- Starch
Folds of Kerckring
Longitudinal folds on SI lumen surface
What does starch break down into?
Maltose
What maltose, trehalose, lactose, and sucrose break down into
Maltose/trehalose -> glucose + glucose
Lactose -> glucose + galactose
Sucrose -> glucose + fructose
Main way to test for CHO assimilation disorders
O/N fast -> ingest 25g D-xylose -> collect urine for next five hours
Positive result of O/N fast for CHO testing
D-xylose should be absorbed but not utilized -> should be a lot in the urine, but if the SI cant absorb it, then there will be less D-xylose in the urine
Breath tests for CHO assimilation disorders
Can test methane, isotopic 13CO2, lactose/sucrose breath tests
What two enzymes activate most of the pancreatic enzymes in the SI?
Trypsin or trypsinogen (enterokinase)
Four classes of AAs
Neutral, basic, acidic, imino
The key feature of protein assimilation disorders
Deficiency of pancreatic enzymes or defect in transporters of intestinal ep cells
Name some dietary fat types
triglycerides (mostly), diglycerides, monoglycerides, FAs, cholesterol esters, phospholipids
Two pancreatic enzymes in lipid digestion secreted as active enzymes
Pancreatic lipase, cholesterol ester hydrolase
What activates colipase?
Trypsin
Overlying theme of lipid assimilation disorders
improper acidity of duodenal contents - lumen here must be neutralized by HCO3 containing pancreatic secretions
Four fat soluble vitamins
ADEK
