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7 Cards in this Set
- Front
- Back
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Chemical breakdown of food by enzymes secreted by....
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glangular cells of mouth
Chief cells in stomach Exocrine cells of pancreas |
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Two types of digestion...
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Cavital digestion-enzymes secreted by salivary glands, stomach and pancreas
Membrane digestion- hydrolysisng enzymes associated with SI brush border |
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Movement of nutrients from lumen into blood is restricted by pathway, consisting of...
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Unstirred aqueous layer
Glycocalyx "fuzzy coat" Cell membrane Cyoplasm of cell Basal/lateral memebrane of cell intracellular space basement membrane Lymph/blood vessel |
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Transport process...
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Pinocytosis- base of microvilli
Passive diffusion- through intracellular spaces or pores in cell membrane Facilitated Diffusion Active transport |
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CHO digestion, which contributes to 50% of our calorie intake, comprises of the following...
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Salivary amylase- 6.5-7.5 pH, parotid and submandibular glands, breaks down polysaccharides to di- and tri-saccharides, is rendered inactive after 2 hour digestion
Duodenum- pancreatic Alpha amylase- breaks down any remaining plysach's to tri and di, but does NOT fully hydrolises di and tri to monosaccharrides Intestinal Muscosa- Sucrase- sucrose to glucose and fructose, Lactase- lactose to galactose and glucost, Maltase-maltose to 2x glucose. Polysaccharides-staarch amylose and amylopectin consist of 1-4 and 1-4 alpha bonds-however, amalyse can only digest 1-4 A bonds- breaks it down to aplpha limit dextrins, maltose and maltatriose-> A.L.D- hydrolised 5% glucoamaylase, 95% isomaltose, Maltose/maltatriose-25% glucoamaylase, 25% sucrase, 50% isomaltase |
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CHO absorption consists of both active and passive diffusion...
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aqueous channels between enthrocytes and pores between brush border membranes- fructose
Membrane carrier system (NA+ dependent)-> owing to larger hexoses unable to fit through aqueous channels/pores-glucose/galactose |
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CHO secondary active transport...
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2 NA+ fpr each glucose molecule, NA-K ATPase maintains an NA gradient which facilitates glucose absorption. (Na exits cell and K enters (3 NA for 2 K)
Na facilitated diffusion of glucose. Exit of glucose from basal lateral membrane is achieved by diffusion or Na independent carrier of glucose |
