NFS 4271 Study Guide - Quiz Guide: Descending Limb Of Loop Of Henle, Bone Density, Aldosterone
17 Sep 2017
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Document Summary
600 g in a 60 kg person. Structural component of bone,teeth,cell membranes, phospholipids,nucleic acids,nucleotide coenzymes, atp, adp, phosphate transferring system in cells, ph regulation. Found in some foods as phytic acid and is less bioavailable(whole grains) Discovered in 1669 by a german alchemist. Hydrolyzed to inorganic phosphate by zinc-containing enzymes such as: Alkaline phosphatase (enzyme) is stimulated by calcitriol and functions at brush border. Occurs mainly in the duodenum and jejunum. Diffusion mainly in proximal duodenum with high intakes. Saturable, carrier-mediated active transport enhanced by calcitriol and low phosphorus intake. Inhibited by phytic acid, excessive mg, al, and ca. Phosphate balance is achieved by renal excretion. Phosphorus in grains is in form of phytate. Humans lack phytase required for liberation of phosphorus, therefore decreasing absorption. Yeast contains phytase so phosphorus from yeast breads are more available. Negative charges on phosphorus bind to positively charged minerals making them unavailable for absorption. (ca, mg, fe & zn)
