Villi are small, finger-like projections that line the inner surface of the small intestine. Their primary function is to increase the surface area of the small intestine for the absorption of nutrients from the digested food.
Here's how villi work:
- Increased Surface Area: Villi, along with microvilli (even smaller projections on the surface of villi), significantly increase the surface area of the small intestine. This increased surface area allows for more efficient absorption of nutrients from the digested food, called chyme.
- Nutrient Absorption: As chyme moves through the small intestine, nutrients are absorbed by the villi. These nutrients then pass into the bloodstream through the capillaries within the villi.
- Transportation: The absorbed nutrients are transported throughout the body, providing energy and building blocks for cells.
- Efficient Digestion: Villi, with their extensive surface area, contribute to the efficient digestion and absorption of nutrients, ensuring optimal nutrient utilization by the body.
In addition to the small intestine, villi are also found in:
- Placenta: Villi in the placenta facilitate the exchange of oxygen and nutrients between the mother and the developing fetus.
- Arachnoid Membrane: Villi in the arachnoid membrane, called arachnoid villi, help to drain cerebrospinal fluid into the venous sinuses.
