villus

vil·lus   (vĭl'əs)    n.   pl. vil·li (vĭl'ī) Biology A minute projection arising from a mucous membrane, especially: One of the numerous vascular projections of the small intestine. One of the fingerlike projections of the chorion that contribute to the formation of the placenta in mammals. Botany A fine, hairlike epidermal outgrowth. [Latin, shaggy hair.]

Main Entry: vil·lus
Pronunciation: 'vil-&s
Function: noun
Inflected Form: plural vil·li /-"I/
: a smallslender vascular process: as a : one of the minute fingerlike processes which more or less thickly cover and give a velvety appearance to the surface of the mucous membrane of thesmall intestine and serve in the absorption of nutriment and of which each has a central blindly ending lacteal surrounded by blood capillaries and covered with epithelium b : one ofthe branching processes of the surface of the chorion of the developing embryo of most mammals that are restricted to particular areas or diffusely arranged and over parts of the surface becomevascular and help to form the placenta

villus vil·lus (vĭl'əs)
n. pl. vil·li (vĭl'ī)

1. A minute projection arising from a mucous membrane, especially one of the vascular projections of the small intestine.

2. Such a projection of the chorion that contributes to placental formation in mammals.

villus

in anatomy any of the small, slender, vascular projections that increase the surface area of a membrane. Important villous membranes include the placenta and the mucous-membrane coating of the small intestine. The villi of the small intestine project into the intestinal cavity, greatly increasing the surface area for food absorption and adding digestive secretions. The villi number about 6,000 to 25,000 per square inch (10 to 40 per square millimetre) of tissue. They are most prevalent at the beginning of the small intestine and diminish in number toward the end of the tract.

Learn more about villus with a free trial on Britannica.com.