NUT 116B LOWER GI QUESTIONS AND ANSWERS
WITH SOLUTIONS!!
Where is most of the digestive function concentrated? Answers :In the duodenum
Where is most absorption occuring? Answers :Between Duodenum and Jejunum (but happens throughout overall)
Describe the general digestion of carbs Answers :Amylases breaks down starches to maltose
other disaccharides broken down to monosac at brush border Monosac abs at apical membrane of epithelial cells via active transport
Exit basolateral membrane via facilitated diffusion into portal vein
Describe the general digestion of proteins? Answers :Broken down by pepsin and pancreatic enzymes into smaller peptides or
aa
Aminopeptidases at brushborder break small peptides to aa
small peptides and aa into enterocyte via active transport (peptides also broken down to aa inside)
Facilitated diffusion into portal vein
Describe the general digestion of fats? Answers :Emulsified by bile salts to allow pancreatic lipase to hydrolyze; forms micelles At brush border, monoglycerides and FFA in micelles; enter via endocytosis and FA transporters
MG and FFA put back into TAGs and put into chylomicrons
Go into LYMPH
What are some of the defining feature of the intestinal tract? Answers :High surface area
Highly vascularized
highly innervated
covered with thick mucin layer
Undigested food that enters the body is considered what? Answers :Antigenic
basically a food antigen
How should food be going through the intestine? (what uptake) Answers :Transcellular
How should food NOT be going through the intestine? (what uptake) Answers :Paracellular
What can get through the intestine when a leaky gut is present? Answers :food antigens
bacteria
toxins
What effects can result from a leaky/inflamed gut? Answers :Blood brain barrier breach
inflammation
autoimmunity
malabsorption and nutrient deficiency
What two tests can be performed to figure out the intergrity of the intestinal mucosa? Answers :Oral D Xylose dose
Oral lactulose with mannitol
How is an oral D xylose work? Answers :Should be absorbed through cells transcellular If you dont see it appear in urine or in serum suggests intestinal problem because it
is not being absorbed
How does oral lactulose with mannitol work? Answers :Lactulose is absorbed paracellularly
Mannitol is absorbed transcellularly
Lactulose:mannitol ratio increases with cell damage (leaky)
What can be the cause of malabsorption? Answers :Impaired digestion
or literally you are not absorbing well
What are the symptoms of malabsorption of macronutrients?
WITH SOLUTIONS!!
Where is most of the digestive function concentrated? Answers :In the duodenum
Where is most absorption occuring? Answers :Between Duodenum and Jejunum (but happens throughout overall)
Describe the general digestion of carbs Answers :Amylases breaks down starches to maltose
other disaccharides broken down to monosac at brush border Monosac abs at apical membrane of epithelial cells via active transport
Exit basolateral membrane via facilitated diffusion into portal vein
Describe the general digestion of proteins? Answers :Broken down by pepsin and pancreatic enzymes into smaller peptides or
aa
Aminopeptidases at brushborder break small peptides to aa
small peptides and aa into enterocyte via active transport (peptides also broken down to aa inside)
Facilitated diffusion into portal vein
Describe the general digestion of fats? Answers :Emulsified by bile salts to allow pancreatic lipase to hydrolyze; forms micelles At brush border, monoglycerides and FFA in micelles; enter via endocytosis and FA transporters
MG and FFA put back into TAGs and put into chylomicrons
Go into LYMPH
What are some of the defining feature of the intestinal tract? Answers :High surface area
Highly vascularized
highly innervated
covered with thick mucin layer
Undigested food that enters the body is considered what? Answers :Antigenic
basically a food antigen
How should food be going through the intestine? (what uptake) Answers :Transcellular
How should food NOT be going through the intestine? (what uptake) Answers :Paracellular
What can get through the intestine when a leaky gut is present? Answers :food antigens
bacteria
toxins
What effects can result from a leaky/inflamed gut? Answers :Blood brain barrier breach
inflammation
autoimmunity
malabsorption and nutrient deficiency
What two tests can be performed to figure out the intergrity of the intestinal mucosa? Answers :Oral D Xylose dose
Oral lactulose with mannitol
How is an oral D xylose work? Answers :Should be absorbed through cells transcellular If you dont see it appear in urine or in serum suggests intestinal problem because it
is not being absorbed
How does oral lactulose with mannitol work? Answers :Lactulose is absorbed paracellularly
Mannitol is absorbed transcellularly
Lactulose:mannitol ratio increases with cell damage (leaky)
What can be the cause of malabsorption? Answers :Impaired digestion
or literally you are not absorbing well
What are the symptoms of malabsorption of macronutrients?
