Download Review

SOME OF THE MANY DIGESTION FACTS TO KNOW
Know all of the notes, worksheets, charts, diagrams , etc
Know significance of all of the following:
Fact: Amylase and lipase deactivated in stomach by acid and protein digestive enzymes
Lipase does not work in the mouth because fat is not emulsified!!!
What commonly ingested substances are absorbed by blood directly from the stomach? (VERY
LITTLE absorbed here! Aspirin, alcohol, and a few other drugs)
Fact: Virtually all absorption of nutrients in the SI
pH of stomach? 2
Fact: Bile--Emulsify fats-physically separates fat into tiny droplets result in large surface
area for the fats--Facilitate fat and cholesterol absorption
Fact: Chief bile pigment=bilirubin (breakdown of heme)
Sphincter of Oddi-guards entry of common bile and pancreatic duct to duodenum
Brunner’s glands-produce alkaline mucus in duodenum to neutralize chyme
Kupffer cells-phagocytic cells in liver-remove debris such as bacteria from blood
Hepatocytes-liver cells that make bile
Fat soluble Vitamins need to be accompanied by fat-A, D, E, K
Hormones that enhance bile production--Secretin and CCK
Only stomach function essential to life? Production of Intrinsic Factor so Vitamin B12 can
be absorbed-important for RBC formation
Gastrin secretion stimulates secretion of gastric juice
Ghrelin secretion->hypothalamus increases appetite
Pyloric Retropulsion-30 ml chyme in pylorus
3 ml chyme released into duodenum
27 ml chyme goes back to stomach to remix
Helicobacter pylori---one of main causes of ulcers in stomach
Route of nutrients from villi? ( Villi mucosa->active transport->capillary blood->hepatic portal
vein to liver -veins to capillaries to veins is called a portal system)
Exception-some lipids absorbed by diffusion into lacteal
Lacteals in villi do? Absorb fats
Where is most water absorbed? Small intestine (even though this is the main function of
the colon)
Which organ has absorption of water as its main function? Colon
Diverticula-- Abnormal pouch or sac on the intestines
Haustra-Normal pouches of the colon
Autoimmune disorders of the digestive tract-- Ulcerative colitis and Crohn Disease
Peyer’s Patches-significance of increase toward the end of the small intestine? (Protect from
bacteria in colon)
Why is it important that only small amounts of chyme be released into SI at a time?
Overwhelm SI if all released at once…..low pH would not allow SI enzymes to work
How is pepsinogen->pepsin an example of a positive feedback process? The more protein in
the stomach the more pepsinogen->pepsin formation
How is this different from negative feedback?
Why don’t the protein-digesting enzymes of pancreas digest the pancreas itself?
(They are released as inactive proenzymes)