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Esdin LS 2 Lec 10 Digestive

Disaccharidases maltase sucrase lactase

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Unformatted text preview: the small intestine contain finger like projections called villi •  Villi increase the surface area The Small Intestine •  Each villus is made of many epithelial cells •  Each epithelial cell contains microvilli (brush border) 16 4/21/13 Brush Border Enzymes •  Enterokinase trypsinogen –  Activates _______ •  Disaccharidases –  Maltase, sucrase, lactase •  Aminopeptidases –  Hydrolyzes peptide fragments to amino acids Carbohydrates Digestion Dietary carbohydrates: starch, glycogen, sucrose, lactose Salivary glands salivary amylase big poly -> little poly Smaller polysaccharides Stomach Pancreas pancreas secretes pancreatic amylase 2 glucose Small intestine poly -> disach glucose/galactose Disacharrides: maltose, sucrose, and lactose glucose/fructose disaccharidases disach -> mono Fructose, glucose, galactose monomers of sugar brush border we have 3 enzymes (disaccharidases) maltase, sucrase and lactase absorption in small intestines 17 4/21/13 Monosaccharide Absorption taking it from site of small intestine to the blood stream Lumen of the small intestine not membrane permeable Maltose Glucose N a+ N a+ N a+ N a+ Na, glucose cotransporter uses glucose upon availability of sodium Apical side lumen of small intestine Maltase K+ cells secondary active transport Facilitated diffusion N a+ K+ K+ K+ intestinal cells ATP N a+ N a+ N a+ N a+ Na/K pump K+ Basal side blood stream Blood fenestrations , openings to get into blood vessel glucose carriers independent of sodium from cells into the blood Monosaccharide Absorption •  Glucose and galactose are absorbed by secondary active transport •  They leave the cells into the plasma via carrier proteins passively 18 4/21/13 liver and muscles are big storage sites Proteins Digestion Dietary Proteins Salivary glands Stomach Pancreas release HCl and intrinsic factor gastric mucosa, (mucosa, chief, parietal) pepsin Small polypeptides Pancreatic trypsinogen and chymotrypsinogen acinar cells, pancreatic enzymes Smaller polypeptides trypsinogen/chymotrypsinogen duct cells release bicarbonate pancreatic procarboxypeptidase Very small peptides and amino acids Small intestine aminopeptidases Amino acids BBE enterokinase activates trypsinogen aminopeptidases Amino Acids Absorption • ...
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