<P> Villi increase the internal surface area of the intestinal walls making available a greater surface area for absorption . 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 . In other words , increased surface area ( in contact with the fluid in the lumen ) decreases the average distance travelled by nutrient molecules , so effectiveness of diffusion increases . The villi are connected to the blood vessels so the circulating blood then carries these nutrients away . </P>
what purpose do villi serve in the small intestine
increase the internal surface area of the intestinal walls