villus /vil″əs/ pl. villi [L, shaggy, hair] , one of the many tiny projections, barely visible to the naked eye, clustered over the entire mucous surface of the small intestine. Villi are covered with epithelium that diffuses and transports fluids and nutrients. They are larger in some parts of the intestine than in others and flatten out when the intestine distends. Each villus has a core of delicate areolar and reticular connective tissue supporting the epithelium, various capillaries, and often a single lymphatic lacteal that fills with milky white chyle during the digestion of a fatty meal. −villous, adj.
