A+-+How+Kidney+Stones+Form

** What? ** Kidney stones, also called Nephrolithiasis, are solid crystals of dissolved minerals in urine forming within kidneys or ureters. They vary in size, from as small as a grain of sand, or as large as a golf ball, but most are less than a third of an inch in diameter. These stones are build-ups of mineral salts and other substances that form in the urinary tract. Many stones are small enough to pass out of the body during urination, but when they partially or fully block the flow of urine, they can cause immense pain. Kidney stones are separated into different types based on their main ingredient: Calcium stones (the most common), Uric acid stones, Crystine stones, and Struvite stones **  How? ** People have previously believed that the formation of kidney stones was encouraged by a large intake of calcium because calcium oxalate stones are most common. However, this is a myth. A Calcium stone is a  crystal of calcium oxalate, CaC2O4, that forms in the kidneys when oxalic acid is present. Calcium oxalate is extremely insoluble in water and consequently, once kidney stones form, they will not readily dissolve.
 * How Do Kidney Stones Form? - Zoe Bundas   **

In general circumstances, the conditions that could be the cause of kidney stones include:

1) A high concentration of stone-forming mineral salts in urine: calcium oxalate, calcium phosphate, or struvite or other such stone-forming substances are found as high levels in urine, crystals can form and become trapped in the urinary tract. Crystals can then attract other crystals and bind together, forming a stone. 2) An uneven balance of acid in urine: stone forming substances remain dissolved depending on the acidity or alkalinity of the urine. Some stones will form in acid urine, and some only in alkaline urine. 3) A lack of substances in the urine that prevent the growth of crystals: pyrophosphates, citrates, and magnesium are substances that inhibit the formation and growth of crystals in the urine. When these substances decrease or are absent, a stone can develop.      As well, kidney stones form when there is a decrease in urine volume and/or an excess of stone-forming substances in the urine. Dehydration caused from a lack of fluid intake or exercise without fluid replacement increases the risk of kidney stones forming. Also, obstructing the flow of urine can also lead to stone formation. They can also result from infection in the urinary tract (which is how struvite stones form). In terms of Struvite stones, the formation is associated with the presence of certain bacteria that split urea into ammonia. These stones contain magnesium, ammonium, and phosphate.       Kidney Stones (Renal Stones, Nephrolithiasis). (n.d.). //Medicine Net//. Retrieved December 9, 2010, from www.medicinenet.com/kidney_stone/article.htm Reactivity: Synthesis of Kidney Stones. (n.d.). //Worcester Polytechnic Institute (WPI)//. Retrieved December 9, 2010, from http://www.wpi.edu/Academics/Depts/Chemistry/Courses/General/caoxalate.html kidney stone. (2007, January 4). //Chemistry Encyclopedia//. Retrieved December 8, 2010, from www.chemistrydaily.com/chemistry/Kidney_stone
 * Kidney Stones. (2009, October 2). //eHealthMD//. Retrieved December 8, 2010, from http://www.ehealthmd.com/library/kidneystones/KS_whatis.html