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→Milk of Magnesia
===Milk of Magnesia===
===Milk of Magnesia===
[[File:UNN_Medical_Geology_Fig_16.png|thumb|400px|{{figure number|16}}Milk of Magnesia (sourced from: www.bing.com/images on 31/03/2014)]]
Milk of magnesia is a name given to magnesium hydroxide – an inorganic compound with the formula, “Mg(OH)2”. It forms a milk-like appearance when in suspension, hence the name. The solid mineral form of magnesium hydroxide is brucite [Mg(OH)2] which occurs in clay minerals especially in chlorite. Brucite occupies the interlayer position which is normally occupied by monovalent and divalent cations such as Na+, K+, Mg+ and Ca+ in chlorite. In this manner, chlorite interlayer is cemented by brucite and can neither swell nor shrink (Zumdahl, 2009).
Milk of magnesia is a name given to magnesium hydroxide – an inorganic compound with the formula, “Mg(OH)2”. It forms a milk-like appearance when in suspension, hence the name. The solid mineral form of magnesium hydroxide is brucite [Mg(OH)2] which occurs in clay minerals especially in chlorite. Brucite occupies the interlayer position which is normally occupied by monovalent and divalent cations such as Na+, K+, Mg+ and Ca+ in chlorite. In this manner, chlorite interlayer is cemented by brucite and can neither swell nor shrink (Zumdahl, 2009).
Milk of magnesia is used as an antacid to neutralize stomach acid. Hydroxide ions from the Mg(OH)2 combine with acidic hydroxide (H+) ions produced from hydrochloric acid by parietal cells in the stomach to produce water. It is made into capsules and chewable tablets for use against constipation and indigestion ().
Milk of magnesia is used as an antacid to neutralize stomach acid. Hydroxide ions from the Mg(OH)2 combine with acidic hydroxide (H+) ions produced from hydrochloric acid by parietal cells in the stomach to produce water. It is made into capsules and chewable tablets for use against constipation and indigestion ([[:File:UNN_Medical_Geology_Fig_16.png|Figure 16]]).
As a laxative, milk of magnesia absorbs fluid from the body, through osmotic pressure, into the lumen of the small intestine while retaining the fluid already in the small intestine (Pradyot, 2002). First, Mg2+ is poorly absorbed from the intestinal tract, so it draws water from the surrounding tissue by osmosis. Not only does this increase the water content, it softens the faeces and increases the volume of faeces in the intestine which naturally stimulates intestinal motility. Furthermore, Mg2+ ions cause the release of cholecystokinin (CCK) which results in intraluminal accumulation of water, electrolytes and increased intestinal motility. This stimulates the nerves of the colon to distend leading to peristalsis culminating in the evacuation of its contents.
As a laxative, milk of magnesia absorbs fluid from the body, through osmotic pressure, into the lumen of the small intestine while retaining the fluid already in the small intestine (Pradyot, 2002). First, Mg2+ is poorly absorbed from the intestinal tract, so it draws water from the surrounding tissue by osmosis. Not only does this increase the water content, it softens the faeces and increases the volume of faeces in the intestine which naturally stimulates intestinal motility. Furthermore, Mg2+ ions cause the release of cholecystokinin (CCK) which results in intraluminal accumulation of water, electrolytes and increased intestinal motility. This stimulates the nerves of the colon to distend leading to peristalsis culminating in the evacuation of its contents.
===Plaster of Paris===
===Plaster of Paris===