Exam 4: Lecture 57: Digestion and Absorption of Carbohydrates Flashcards
What is digestion?
Chemical and mechanical breakdown of ingested food into absorbable molecules
What is absorption?
Movement of macronutrients, water, electrolytes from intestinal lumen into blood
What are the two paths of absorption?
Transcellular and paracellular
What is the difference between transcellular and paracellular absorption?
Transcellular crosses the luminal membrane through passive diffusion or transporters.
Paracellular moves substances across tight junctions between intestinal epithelial cells
Folds of Kerckring are found where?
In the intestinal mucosa
Why are there Folds of Kerckring with microvilli in the intestinal mucosa?
Increase surface area, slows digesta movement
Which portion of the small intestine have the longest villi?
Duodenum
What constitutes the brush border?
The microvilli that line the surface of epithelial cells
What is the turnover rate for gastric epithelial cells?
3-6 days
What species have a natural diet high in cellulose?
Horses, cattle, and sheep
What is the main carbohydrate in grain?
Startch
Chickens and pigs are usually fed a commercial diet high in what?
Grain/startch
What type of natural diet do dogs have?
Omnivore - do well with starch and some soluble fiber
What is the main carb source for cats on a prey diet?
Glycogen
What is the primary source of energy for most cells?
Glucose