The rumen epithelium is the tissue which lines the largest of the four fore stomachs in the ruminant animal -cows and sheep. Rumen epithelial cells are important because they are responsible for the absorption of nutrients from the rumen into the blood. [ http://www.ncbi.nlm.nih.gov/pubmed/10764086 http://purl.obolibrary.org/obo/BTO_0001195 ]