Term
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Definition
| tofu, corn tortillas, msutard and turnip greens, broccoli, legumes, small fish with bones, calcium fortified OJ |
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Term
| Calcium:absoprtion overview |
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Definition
-range from diet is 20-50%
-dairy products have highest absorption
-two main transport processes
A) transcellular
B) paracellular |
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Term
| Calcium: absoprtion: transcellular |
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Definition
-primarily in duodenum and proximal jejunum
-saturable, requires energy, involves calbindin and requires calcitrol
-stimulated on ingestion of low calcium diets |
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Term
| Calcium: absorption: transcellular: 3 steps |
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Definition
1) transport across BB membrane
2) intracellular movement
3) extrusion across basolateral membrane |
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Term
| Calcium: absorption: paracellular |
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Definition
| energy independent and takes place only when [Ca] in lumen are very high, Ca just squeezes b/w enterocytes |
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Term
| Calcium: enhancers of absoprtion |
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Definition
| Vit. D and lactose, increase solubility |
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Term
| Calcium: inhibitors of calcium |
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Definition
| phytates and oxalates, form kelates with Ca so Ca can't get absorbed |
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Term
| Calcium: functions: corticol bone |
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Definition
-compact
-consists of layers of mineralized protein collagen |
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Term
| Calcium: functions: trabecular bone |
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Definition
-spongy
-consists of interconnected system of mineralized protein
-more active metabolically, goes thru bone resorption |
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Term
| Calcium: functions: bone resoprtion |
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Definition
-osteoclasts have lysosomal capabilities
-increase PTH -> binds to PTHR -> increases RANKL (on osteoblasts) -> binds to receptor of preosteoclast -> maturation to osteoclasts -> degradation of bone matrix |
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Term
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Definition
-secretion (exocytosis): of insulin from B cells, excitation -> muscle contration
-stabilization of membrane potentials
-enzyme cofactor (ie in blood coagulation)
-2nd messanger |
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