Function
In all humans, the villi together increase intestinal absorptive surface area approximately 30-fold and 60-fold, respectively, providing exceptionally efficient absorption of nutrients in the lumen. This increases the surface area so there are more places for food to be absorbed.
There are also enzymes on the surface for digestion. Villus capillaries collect amino acids and simple sugars taken up by the villi into the blood stream. Villus lacteals (Lymph capillary) collect absorbed chylomicrons, which are lipoproteins composed of triglycerides, cholesterol and amphipathic proteins, and are taken to the rest of the body through the Lymph fluid.
Villi are specialised for absorption in the small intestine as they have a thin wall, about 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. They have a rich blood supply to keep a concentration gradient.
Villi also help the intestines to move food along the digestive pathway.
Read more about this topic: Intestinal Villus
Famous quotes containing the word function:
“It is the function of vice to keep virtue within reasonable bounds.”
—Samuel Butler (1835–1902)
“Any translation which intends to perform a transmitting function cannot transmit anything but information—hence, something inessential. This is the hallmark of bad translations.”
—Walter Benjamin (1892–1940)
“To look backward for a while is to refresh the eye, to restore it, and to render it the more fit for its prime function of looking forward.”
—Margaret Fairless Barber (1869–1901)