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37 Cards in this Set
- Front
- Back
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Salivary amylaase hydrolyzes starch into _______
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Oligosaccharides
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At what pH does salivary amylase function best at?
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6.8 to 7
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At what pH does amylase denatured and unfunctional?
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lower than 4.5
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What percent of starch is digested before it reaches the small intestine
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50%
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When is starch completely coverted to oligosaccharides and maltose?
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When the chyme mixes with pancreatic amylase
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What are two brush border enzymes that hydrolize oligosaccharides that are three or more residues long?
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Extrinase and glucoamylase
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What is the third brush border enzyme that hydrolyzes maltose to glucose?
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Maltase
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What are the major dietary disaccharides?
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Sucrose and lactose
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What enzymes digest sucrose and lactose?
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Sucrase and lactase
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What percentage of absorbed sugar is glucose and by which mechanism is it taken up?
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80%. Sodium-glucose transport protein (SGLT)
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What increases the osmolarity of the extracellular fluid in carbohydrate absorption
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Sugar
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This is when water carries glucose and other nutrients with it
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Solvent drag
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after a high carb meal which absorbs more: solvent drag or Sodium-glucose transport?
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Solvent drag absorbs 2 to 3 times more glucose
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Other than glucose, what else does sodium-glucose transport absorb?
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Galactose
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What three sources do amino acids come from?
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1.)dietary proteins
2.) Enzymes digesting other enzymes 3.) And sloughed epithelial cells digested by these enzymes |
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What are enzymes that digest proteins called?
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Proteases
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In the small intestine, these pancreatic enzymes take over protein digestion by hydrolyzing polypeptides into even shorter oligopeptides
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trypsin and chymotripsin
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The further breakdown of the shorter oligopeptides by these three enzymes
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1.) carboxypeptidase
2.)aminopeptidase 3.)Dipeptidase |
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Infants digest intact protein through this mechanism
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pinocytosis
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What are the enzymes called that digest fats
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lipases
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Where does the most fat digestion occur?
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In the small intestine through the action of pancreatic lipase
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Large fat globules is further broken down into _____ _____ by certain compenents of the bile.
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Emulification droplets
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What are the products of lipase action
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Two free fatty acids and one monoglyceride.
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What are micelles?
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They are minute droplets made in the liver consisting of 20 to 40 bile acid molecules. Transport lipids to the surfaces of the intestinal absorptive cells.
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Within the intestinal cell, the FFA's and monoglycerides are transported into the smooth ER and resynthesized into triglycerides. The golgi complex combines these with a film of phospholipids and protein, forming droplets called .....
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Chylomicrons
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What do nucleosidases and phosphatases of the brush border do?
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decompose the nucleotides into phosphate ions, ribose or deoxyribose, and nitrogenous bases.
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What are the fat-soluble vitamins that are absorbed with other lipids?
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A, D, E, K
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Where are minerals absorbed in the small intestine
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HA GOTCHA! Along the entire length dummy.
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These minerals are absorbed only to the body's needs unlike other minerals that leave it up to the kidneys to filter out excess
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Calcium and Iron
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What stimulates Iron absorption?
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Liver hormone hepcidin
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How are ferrous ions taken up?
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the extracellular protein transferrin
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How is calcium absorbed in the duodenum
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active transport
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How is calcium absorbed in the ileum and jejunum?
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diffusion between epithelial cells
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Once calcium is inside the cell it binds to a protein called ________
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calbindin
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During a drop in calcium levels, What are the three ways that vitamin D effects the absorptive cells of the duodenum
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1.) Increases the number of calcium channels
2.) Increasies the amount of calbindin 3.) Increases the number of calcium--ATPase pumps |
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How much water is excreted with the feces?
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.2 L
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How much water does the digestive tract recieve?
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9 L
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