Why is the ninth month called September?
villus vil·lus (vĭl'əs)
n. pl. vil·li (vĭl'ī)
A minute projection arising from a mucous membrane, especially one of the vascular projections of the small intestine.
Such a projection of the chorion that contributes to placental formation in mammals.
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.