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Side A ------ Side B
Fat digestion and absorption primarily occurs in the _________ ------ Small intestine, duodenum primarily
T/F.  Fat digestion typically occurs in the stomach. ------ FALSE.  It is most commonly in the small intestine.
What are the 5 components of fat absorption? ------ 1. Bile salts2. Pancreatic enzymes3. Alkaline pH4. Absorptive surface5. Enterohepatic circulation (of bile salts at the terminal ileum)
What is intussusception? ------ Invagination of one segment of the GI tract into another segment, may cut off blood supply and cause necrosis of a segment of bowel, loss of mucosal surface area.
What is volvulus? ------ Twisting of the mesentery with blood supply/innervation to the  bowels, can cause necrosis of the bowel and loss of mucosal surface area.
What is necrotizing enterocolitis? ------ Unknown cause, infant born with necrosed segment of bowel.  Lose mucosal surface area, unable to digest/absorb all of the carbohydrates needed.
What are 3 causes of short bowel syndrome? ------ 1. Necrotizing enterocolitis (NEC)2. Volvulus3. Intussusception
What is short bowel syndrome? ------ Not necessarily due to length, but due to a functional loss of mucosal surface area
What is the typical histologic finding when there is damage to the villi? ------ Villi are blunted on histologic specimens - villi normally look like shag carpet with numerous folds, but when damaged they are blunted and the mucosa looks smooth.
How does celiac disease usually present? ------ When the baby is switched from breast-feeding to cereal, start producing antibodies to gluten.  The damage to the villi and symptoms are insiduous - slowly start to have diarrhea and failure to thrive.
What is celiac disease? ------ Autoimmune disease - antibodies to gluten (carbohydrate found in wheat and barley), causes inflammatory reaction that damages the villi of the small intestine
How does viral gastroenteritis cause damage to villi? ------ It causes blunting of villi and causes temporary loss of lactase and sucrase-isomaltase, which takes 2 weeks to regenerate
Which virus usu causes damage to the villi? ------ Rotavirus
What are the 3 typical causes of villous damage? ------ 1) Viral gastroenteritis2) Celiac disease3) Tropical sprue
What is sucrase-isomaltase deficiency? ------ Can't digest sucrose or isomaltose, so have diarrhea and failure to thrive.
What is congenital lactase deficiency? ------ Newborns have no lactase, so have diarrhea from first feed.  Very rare.
T/F.  Lactose intolerance is more common in blacks than whites. ------ True.
Lactase deficiency is also known as _________ ------ Lactose intolerance.
Lactase deficiency ------ Decrease in lactase after weaning which is usu due to genetics (more common in blacks), usu a problem of older children and adults
What are the 3 selective disaccharidase deficiencies? ------ 1. Lactase deficiency2. Congenital lactase deficiency3. Sucrase-isomaltase deficiency
What are the clinical consequences of carbohydrate malabsorption? ------ Undigested sugars exert an osmotic pull into the lumen --> increased intestinal motility --> watery diarrhea 
What are 3 causes of carbohydrate malabsorption? ------ 1. Selective deficiency of disaccharidases (sucrase-isomaltase, lactase)2. Villous damage (viral gastroenteritis, celiac disease, tropical sprue)3. Loss of mucosal surface (short bowel syndrome)
How do the tight junctions in the epithelium change as you move down the digestive tract? ------ They become tighter/less leaky as you move from SI to LI, so that by the time you reach the colon only water is being absorbed (and not really any nutrients)
Most problems with carbohydrate absorption will be due to __________________ ------ Malfunction of disaccharides at the level of the villus, NOT pancreatic amylases
T/F.  Even minor injury to the pancreas can cause a severe depletion of pancreatic amylase. ------ FALSE.  You have to really damage the pancreas to have a significant decrease in pancreatic amylase.
What are 3 conditions that affect the production/release of pancreatic amylase? ------ 1. Cystic fibrosis2. Chronic pancreatitis3. Surgical resection of the pancreas
T/F.  Salivary amylase is the most important enzyme for the digestion of starch. ------ FALSE.  Minor role.  Major role is pancreatic amylase.
T/F.  The body can absorb both monosaccharides and disaccharides, but not poylsaccharides. ------ FALSE.  The body can only absorb monosaccharides.
Describe the distribution of the carbohydrates that we eat. ------ Starch = 60%Sucrose = 30%Lactose = 10%
T/F.  Malabsorption incorporates both maldigestion and malabsorption. ------ True.  Maldigestion is the inability to digest substances, and malabsorption is the inability to transport digested substances across the lumen into the mucosa.
How is carbohydrate usually digested and absorbed in the GI tract? ------ Salivary amylase and pancreatic amylase break down starch into dissacharides, then disaccharidases in the villi/microvilli of the intestine break down disaccharides into monosaccharides.
What is necessary for fat digestion? ------ Bile salts, in order to form micelles.  Micelles deliver the fatty acids to the villi of the intestines.
Pancreatic enzymes need an alkaline/acidic pH to work. ------ Alkaline pH.
What is enterohepatic circulation? ------ Absorption of bile salts from the terminal ileum.
What are the clinical consequences of fat malabsorption? ------ 1. No osmotic pull so stools are not watery.2. Greasy, floating, offensive stools (steatorrhea)3. Failure to thrive4. Increased appetite (pancreatic insufficiency)5. Fat soluble vitamin malabsorption (ADEK)6. Fat may be detected in stool (quantitative - 72 hr collection; qualitative - Sudan test)
What 4 things can cause insufficient bile acids? ------ 1. Cancer- bile duct2. Biliary atresia3. Cirrhosis4. Gallstone
What often accompanies insufficient bile acids and why? ------ Jaundice, because if unable to release bile, also unable to release bilirubin, and more bilirubin will get into blood to cause jaundice.
What is biliary atresia? ------ Disorder in newborns in which the common bile duct is obstructed or absent
What are the 2 mechanisms of insufficient pancreatic enzymes? ------ 1) Pancreatic insufficiency2) Acidic duodenal contents
What are 2 types of pancreatic insufficiency that leads to insufficient pancreatic enzymes? ------ 1) Cystic fibrosis2) Surgical resection of the pancreas
What are 2 conditions causing acidic duodenal contents? ------ 1) Rapid gastric emptying (too much acid for duodenum to buffer, can be caused by gastrectomy or vagotomy)2) Zollinger-Ellison syndrome = increases secretion of gastrin, so chyme from stomach is super acidic and can't be buffered enough
What are the 4 disorders of the absorptive surface that leads to fat malabsorption? ------ 1. Surgical resection2. Celiac disease3. Whipple's disease4. Abetalipoproteinemia
What is abetalipoproteinemia? ------ Autosomal recessive disorder resulting in lack of the MTTP gene (mitochondrial triglyceride transfer protein), which is responsible for formation of chylomicrons.  No chylomicrons form -->  so chylomicron and VLDL levels are low or absent.Presents early in infancy, can see fat in enterocytes.  Also see acanthocytes in blood film, which are spur-like RBCs whose membranes contain more cholesterol relative to phospholipids.
What are the 2 lymphatic disorders that can lead to fat malabsroption? ------ 1. Lymphangiectasia2. Retroperitoneal fibrosis
What is lymphangiectasia? ------ Pathologic dilation of the lymphatic vessels, leads to decrease in flow of lymph, leading to blockage of fat circulation/absorption
What are 2 ways that enterohepatic circulation interruption can lead to fat malabsorption? ------ 1) Surgical resection (of the terminal ileum)2) Crohn's disease
What are the 4 principal components of protein absorption? ------ 1. Pepsin2. Pancreatic proteases3. Enterokinases4. Absorptive surface
Protein absorption - pepsin ------ Pepsin starts the breakdown of proteins in the stomach.  It is only active at pH < 4 (acidic), so when pH of the stomach begins to rise, pepsin shuts off. (Recall: acid cleaves pepsinogen to pepsin, so need acidc pH for pepsin to be active).  When pH starts to rise, pancreatic enzymes take over (require alkaline pH to be active).
What enzyme is necessary to activate the pancreatic proteases? ------ EnterokinaseEnterokinase cleaves trypsinogen --> trypsin, and trypsin is necessary to activate all other pancreatic protease zymogens.
In what form are proteins absorbed? ------ Amino acids and small peptides.  This is beneficial because if amino acids can't be absorbed for some reason, can just absorb them as part of a small peptide - 2 mechanisms, so not as many problems with protein malabsorption.
T/F.  There are more problems with protein malabsorption than carbohydrate or fat malabsorption. ------ FALSE.  Less problems because there are 2 ways to get protein absorbed (amino acids and small peptides).
What are the 3 main clinical features of protein malabsorption? ------ Poor growth/weight lossHypoalbuminemiaEdema
What are the 4 causes of protein malabsorption? ------ 1. Decreased intake (malnutrition)2. Decreased absorption (malabsorption)3. Liver failure4. Increased loss (kidney- nephrotic syndrome, gut- protein losing enteropathy)
Rare diseases involving protein malabsorption - name 5 ------ 1. Primary enterokinase deficiency2. Cystinuria3. Giardia infection4. Cobalamin5.
Vitamin B12 is reabsorbed in what part of the GI tract? ------ Ileum

Side A ------ Side B
Fat digestion and absorption primarily occurs in the _________ ------ Small intestine, duodenum primarily
T/F.  Fat digestion typically occurs in the stomach. ------ FALSE.  It is most commonly in the small intestine.
What are the 5 components of fat absorption? ------ 1. Bile salts2. Pancreatic enzymes3. Alkaline pH4. Absorptive surface5. Enterohepatic circulation (of bile salts at the terminal ileum)
What is intussusception? ------ Invagination of one segment of the GI tract into another segment, may cut off blood supply and cause necrosis of a segment of bowel, loss of mucosal surface area.
What is volvulus? ------ Twisting of the mesentery with blood supply/innervation to the  bowels, can cause necrosis of the bowel and loss of mucosal surface area.
What is necrotizing enterocolitis? ------ Unknown cause, infant born with necrosed segment of bowel.  Lose mucosal surface area, unable to digest/absorb all of the carbohydrates needed.
What are 3 causes of short bowel syndrome? ------ 1. Necrotizing enterocolitis (NEC)2. Volvulus3. Intussusception
What is short bowel syndrome? ------ Not necessarily due to length, but due to a functional loss of mucosal surface area
What is the typical histologic finding when there is damage to the villi? ------ Villi are blunted on histologic specimens - villi normally look like shag carpet with numerous folds, but when damaged they are blunted and the mucosa looks smooth.
How does celiac disease usually present? ------ When the baby is switched from breast-feeding to cereal, start producing antibodies to gluten.  The damage to the villi and symptoms are insiduous - slowly start to have diarrhea and failure to thrive.
What is celiac disease? ------ Autoimmune disease - antibodies to gluten (carbohydrate found in wheat and barley), causes inflammatory reaction that damages the villi of the small intestine
How does viral gastroenteritis cause damage to villi? ------ It causes blunting of villi and causes temporary loss of lactase and sucrase-isomaltase, which takes 2 weeks to regenerate
Which virus usu causes damage to the villi? ------ Rotavirus
What are the 3 typical causes of villous damage? ------ 1) Viral gastroenteritis2) Celiac disease3) Tropical sprue
What is sucrase-isomaltase deficiency? ------ Can't digest sucrose or isomaltose, so have diarrhea and failure to thrive.
What is congenital lactase deficiency? ------ Newborns have no lactase, so have diarrhea from first feed.  Very rare.
T/F.  Lactose intolerance is more common in blacks than whites. ------ True.
Lactase deficiency is also known as _________ ------ Lactose intolerance.
Lactase deficiency ------ Decrease in lactase after weaning which is usu due to genetics (more common in blacks), usu a problem of older children and adults
What are the 3 selective disaccharidase deficiencies? ------ 1. Lactase deficiency2. Congenital lactase deficiency3. Sucrase-isomaltase deficiency
What are the clinical consequences of carbohydrate malabsorption? ------ Undigested sugars exert an osmotic pull into the lumen --> increased intestinal motility --> watery diarrhea 
What are 3 causes of carbohydrate malabsorption? ------ 1. Selective deficiency of disaccharidases (sucrase-isomaltase, lactase)2. Villous damage (viral gastroenteritis, celiac disease, tropical sprue)3. Loss of mucosal surface (short bowel syndrome)
How do the tight junctions in the epithelium change as you move down the digestive tract? ------ They become tighter/less leaky as you move from SI to LI, so that by the time you reach the colon only water is being absorbed (and not really any nutrients)
Most problems with carbohydrate absorption will be due to __________________ ------ Malfunction of disaccharides at the level of the villus, NOT pancreatic amylases
T/F.  Even minor injury to the pancreas can cause a severe depletion of pancreatic amylase. ------ FALSE.  You have to really damage the pancreas to have a significant decrease in pancreatic amylase.
What are 3 conditions that affect the production/release of pancreatic amylase? ------ 1. Cystic fibrosis2. Chronic pancreatitis3. Surgical resection of the pancreas
T/F.  Salivary amylase is the most important enzyme for the digestion of starch. ------ FALSE.  Minor role.  Major role is pancreatic amylase.
T/F.  The body can absorb both monosaccharides and disaccharides, but not poylsaccharides. ------ FALSE.  The body can only absorb monosaccharides.
Describe the distribution of the carbohydrates that we eat. ------ Starch = 60%Sucrose = 30%Lactose = 10%
T/F.  Malabsorption incorporates both maldigestion and malabsorption. ------ True.  Maldigestion is the inability to digest substances, and malabsorption is the inability to transport digested substances across the lumen into the mucosa.
How is carbohydrate usually digested and absorbed in the GI tract? ------ Salivary amylase and pancreatic amylase break down starch into dissacharides, then disaccharidases in the villi/microvilli of the intestine break down disaccharides into monosaccharides.
What is necessary for fat digestion? ------ Bile salts, in order to form micelles.  Micelles deliver the fatty acids to the villi of the intestines.
Pancreatic enzymes need an alkaline/acidic pH to work. ------ Alkaline pH.
What is enterohepatic circulation? ------ Absorption of bile salts from the terminal ileum.
What are the clinical consequences of fat malabsorption? ------ 1. No osmotic pull so stools are not watery.2. Greasy, floating, offensive stools (steatorrhea)3. Failure to thrive4. Increased appetite (pancreatic insufficiency)5. Fat soluble vitamin malabsorption (ADEK)6. Fat may be detected in stool (quantitative - 72 hr collection; qualitative - Sudan test)
What 4 things can cause insufficient bile acids? ------ 1. Cancer- bile duct2. Biliary atresia3. Cirrhosis4. Gallstone
What often accompanies insufficient bile acids and why? ------ Jaundice, because if unable to release bile, also unable to release bilirubin, and more bilirubin will get into blood to cause jaundice.
What is biliary atresia? ------ Disorder in newborns in which the common bile duct is obstructed or absent
What are the 2 mechanisms of insufficient pancreatic enzymes? ------ 1) Pancreatic insufficiency2) Acidic duodenal contents
What are 2 types of pancreatic insufficiency that leads to insufficient pancreatic enzymes? ------ 1) Cystic fibrosis2) Surgical resection of the pancreas
What are 2 conditions causing acidic duodenal contents? ------ 1) Rapid gastric emptying (too much acid for duodenum to buffer, can be caused by gastrectomy or vagotomy)2) Zollinger-Ellison syndrome = increases secretion of gastrin, so chyme from stomach is super acidic and can't be buffered enough
What are the 4 disorders of the absorptive surface that leads to fat malabsorption? ------ 1. Surgical resection2. Celiac disease3. Whipple's disease4. Abetalipoproteinemia
What is abetalipoproteinemia? ------ Autosomal recessive disorder resulting in lack of the MTTP gene (mitochondrial triglyceride transfer protein), which is responsible for formation of chylomicrons.  No chylomicrons form -->  so chylomicron and VLDL levels are low or absent.Presents early in infancy, can see fat in enterocytes.  Also see acanthocytes in blood film, which are spur-like RBCs whose membranes contain more cholesterol relative to phospholipids.
What are the 2 lymphatic disorders that can lead to fat malabsroption? ------ 1. Lymphangiectasia2. Retroperitoneal fibrosis
What is lymphangiectasia? ------ Pathologic dilation of the lymphatic vessels, leads to decrease in flow of lymph, leading to blockage of fat circulation/absorption
What are 2 ways that enterohepatic circulation interruption can lead to fat malabsorption? ------ 1) Surgical resection (of the terminal ileum)2) Crohn's disease
What are the 4 principal components of protein absorption? ------ 1. Pepsin2. Pancreatic proteases3. Enterokinases4. Absorptive surface
Protein absorption - pepsin ------ Pepsin starts the breakdown of proteins in the stomach.  It is only active at pH < 4 (acidic), so when pH of the stomach begins to rise, pepsin shuts off. (Recall: acid cleaves pepsinogen to pepsin, so need acidc pH for pepsin to be active).  When pH starts to rise, pancreatic enzymes take over (require alkaline pH to be active).
What enzyme is necessary to activate the pancreatic proteases? ------ EnterokinaseEnterokinase cleaves trypsinogen --> trypsin, and trypsin is necessary to activate all other pancreatic protease zymogens.
In what form are proteins absorbed? ------ Amino acids and small peptides.  This is beneficial because if amino acids can't be absorbed for some reason, can just absorb them as part of a small peptide - 2 mechanisms, so not as many problems with protein malabsorption.
T/F.  There are more problems with protein malabsorption than carbohydrate or fat malabsorption. ------ FALSE.  Less problems because there are 2 ways to get protein absorbed (amino acids and small peptides).
What are the 3 main clinical features of protein malabsorption? ------ Poor growth/weight lossHypoalbuminemiaEdema
What are the 4 causes of protein malabsorption? ------ 1. Decreased intake (malnutrition)2. Decreased absorption (malabsorption)3. Liver failure4. Increased loss (kidney- nephrotic syndrome, gut- protein losing enteropathy)
Rare diseases involving protein malabsorption - name 5 ------ 1. Primary enterokinase deficiency2. Cystinuria3. Giardia infection4. Cobalamin5.
Vitamin B12 is reabsorbed in what part of the GI tract? ------ Ileum