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30 Cards in this Set
- Front
- Back
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What type of reaction is used to break down ingested nutrients (fats, carbs and proteins)?
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enzyme mediated hydrolysis
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Fats are broken down into ...
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fatty acid + glycerol
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Proteins are broken into ...
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amino acid monomers
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What is ptyalin?
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amylase enzyme in saliva
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Why doesn't salivary amylase work in the stomach?
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pH is too acidic
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What is the difference between salivary and pancreatic amylase?
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pancreatic amylase is much stronger
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Where are the carbohydrate digestive enzymes (sucrase, lactase, dextrinase etc.) found?
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on the brush border of enterocytes in small intestine
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Lactose splits into which monomers?
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glucose + galactose
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Sucrose splits into which monomers?
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fructose + glucose
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Maltose splits into which monomers?
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glucose + glucose
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Hydrolysis of proteins results in breaking of which bonds?
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peptide linkages
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Where is pepsin found?
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stomach, from pepsinogen of chief cells
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Pepsin function
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protease, cleave proteins (collagen)
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What pancreatic enzymes cleave proteins?
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trypsin, chymotrypsin, carboxypolypeptidase
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Lipase function
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digest fats into fatty acid + glycerol
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Bile function
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emulsify + agitate fats by decreasing surface tension
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Micelle function of bile
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carry fatty acid + glycerol to the brush border to be taken into the enterocytes
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3 features of the small intestine to increase surface area
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plicae circularis (valves of Kerckring), villi, microvilli
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What can be absorbed through the stomach?
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alcohol, aspirin, lipid soluble things
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How are amino acids and glucose taken into enterocytes?
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co transport with Na+ (secondary active transport)
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Aldosterone has what effect on absorption?
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increases glucose, amino acid absorption
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In the upper intestine (duodenum and jejunum), what happens to bicarbonate?
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bicarbonate is absorbed. Na/H exchange pumps H+ into the lumen > H+ combines with bicarbonate from the pancreas > H2CO3 dissociates into H2O+CO2 > CO2 goes back into the blood > CO2 reforms bicarbonate in the blood
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In the lower intestine (ileum), what happens to bicarbonate?
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bicarbonate is secreted. exchange with Cl- that is absorbed
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How are calcium, phosphate, and magnesium absorbed form the intestines?
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active transport
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How is galactose absorbed by enterocytes?
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same as glucose
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How is fructose absorbed by enterocytes?
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facilitated diffusion
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Fats that are absorbed in the intestines are made into chylomicrons. How do these enter blood circulation?
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lymphatics > veins > arteries
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Colon function
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absorb water and electrolytes
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What happens to bicarbonate ions in the colon?
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bicarbonate is secreted into the lumen in the colon (exchange for Cl-)
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Brown color of feces if due to ...
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bilirubin breakdown products (stercobilin, urobilin)
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