Each villus is approximately 0.5–1.6 mm in length (in humans), and has many microvilli projecting from the enterocytes of its epithelium which collectively form the striated or brush border.

An increased absorptive area is useful because digested nutrients (including monosaccharide and amino acids) pass into the semipermeable villi through diffusion, which is effective only at short distances.

Villus capillaries collect amino acids and simple sugars taken up by the villi into the blood stream.

Villi are specialized for absorption in the small intestine as they have a thin wall, one cell thick, which enables a shorter diffusion path.

They have a large surface area so there will be more efficient absorption of fatty acids and glycerol into the blood stream.