GI physio Flashcards
(73 cards)
function of the GI system
Ingest food and liquid with nutrients
digest large molecules in ingested food into absorbable molecular forms
absorption of nutrients from the gut
metabolic transform of fuel molecules
detox of foreign substance (liver)
Elimination of metabolic end product secreted by the liver
immune function
where does GI tissue start to have the same structure
From the mid-esophagus all the way down
what does the surface of microvilli of the GI contain
Brush border
how fast does the intestinal epithelial cells turn over
17 billion new cells each day
complete turnover
complete turnover every 5 days
what is the vein associated with GI tissue
Hepatic portal vein
what is the roll of lymph vessels in the GI tract
transport breakdown products for recycling
what is the roll of muscles and nerves of the GI
peristallic movements
what does the brush border do to breakdown food
Contains enzymes
what are the 5 basic
Carbs Proteins Fats Vitamins Minerals
what is the intermediate product of carbs
Maltose
what breaks up polysaccharides
Amylase
what breaks up triglycerides
Lipase
where does Amylase come rom
Saliva and pancreas
what does the breakdown of carbs lead to
Disaccharide maltose
mix of short branched chains of glucose molecules
what breaks down maltose an ingested sucrose and lactose
enzymes located on the apical membranes of small intestine epithelial cells (brush border)
where are most ingested carbs digested and absorbed
first 20% of small intestin
what are the steps of carbohydrate breakdown in the lumen to be absorbed into the intestinal epithelial cells
Polysaccharides broken into maltose via pancreatic amylase
brush border enzymes break maltose and ingested disaccharised into monsaccharides(fructose, glucose, galactose
how does Fructose get into the interstinal epithelial cells
GLUT5
how does Glucose and galactose get intot he intestinal epithelium
SGLT, cotransported with Na
how does Fructose, Glucose and Galactose get into the interstitial fluid
Via GLUT2
what keeps Na out of the cell after SGLT cotransports it in
Na/K ATPase
what are the enzymes invovled in breaking down complex carbs into monosaccharides
DIgestive Enzymes (amylase) Ectoenzymes (lactase)
what breaks down proteins in the stomach
PEpsin
what breaks down proteins in the small intestin
Trypsin
Chymotrypsin
