View source for Omasum



==Overview==
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The ''' omasum''', also known as the '''bible'''<ref name="Chambers">[http://www.chambersharrap.co.uk/chambers/index.shtml The Chambers Dictionary, Ninth Edition, Chambers Harrap Publishers, 2003]</ref>, the '''fardel'''<ref name="Chambers"/>, the '''manyplies'''<ref name="Chambers"/> and the '''psalterium'''<ref name="Chambers"/>, is the third compartment of the stomach in [[ruminants]].  Though its functions have not been well-studied, it appears to primarily aid in the absorption of water, magnesium, and the volatile fatty acids produced by rumen fermentation.  The numerous folds of its mucosa are thought to trap digesta particles to increase their residence time for this said absorption.  

There is some evidence that the contractions of the omasum can propel large particles backwards through the [[reticulorumen orifice]], the junction connecting the omasum with the reticulorumen, into the [[reticulorumen]], the first compartment of the ruminant stomach.  In this way, the omasum allows large particles, which still likely contain appreciable amounts of fermentable substrate, to be further digested in the reticulorumen.  (Though fermentation initiated in the [[reticulorumen]] can continue in the omasum, it does so in only limited quantities, so this mechanism of ejecting largely unfermented particles into the reticulorumen is necessary for complete fermentation.)

[[Category:Animal anatomy]]
[[Category:Digestive system]]

== References ==
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[[Category:Even-toed ungulates]]
[[Category:Animal anatomy]]

[[de:Blättermagen]]
[[eo:Omaso]]
[[fr:Feuillet (organe)]]
[[it:Omaso]]
[[ja:センマイ]]
[[pl:Księgi]]
[[pt:Omaso]]
[[sv:Bladmage]]
[[wa:Cint-fouyeas]]
[[zh:牛百頁]]

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