BIOL 103 Chapter Notes -Omasum, Rumen, Cud
11 Mar 2014
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Document Summary
Herbivores with complex stomachs consisting of several chambers, beginning with 3 outpouchings of the lower esophagus-->forestomach: rumen, reticulum, omasum. Rumen + reticulum: contains microbes that digest cellulose. Microbes break down cellulose into monosacch. that can be absorbed. ->bacteria and protists predigest the food for the animal. Omasum: absorbs some water and salts released from the chewed and partially digested food. Partially digested food (cud) sometimes regurgitated, rechewed, and swallowed again. Eventually cud, ,microbes, and by-products of microbial digestion reach the true stomach: abomasum. ->contains acid and proteolytic enzymes common in other vertebrates. Material passes to intestines; digestion + absorption completed. Some microbes remain in the rumen and multiply to replenish pop"n. Highly efficient way to extract as much nutrients out of food as possible. Food moves from esophagus to crop: storage unit; dilation of lower esophagus. Sometimes material regurgitated from crop to feed young (eg. birds)
