Villi are finger-like projections found in the inner lining of the small intestine. They play a crucial role in the absorption of nutrients by increasing the surface area available for absorption. Here is a detailed overview of the location and function of villi:
Location:
- Villi are found in the inner walls of the small intestine.
- They project into the intestinal cavity, greatly increasing the surface area for food absorption and adding digestive secretions.
- The number of villi decreases as you move from the beginning of the small intestine to the end of the tract.
Function:
- Absorption: Villi enhance the absorption surface area, allowing for the efficient absorption of nutrients.
- Blood Vessels: Each villus has a central core composed of one artery and one vein, which transport proteins and carbohydrates absorbed by the cells of the villi.
- Lymphatic Capillary: Villi contain a centrally located lymphatic capillary (lacteal) that removes droplets of emulsified fat (chyle).
- Movement: Villi move in swaying, contracting motions, believed to increase the flow of blood and lymph and enhance absorption.
- Nutrient Absorption: The inside of the small intestine is lined with villi that absorb nutrients from the liquid mixture called chyme produced in the stomach from the food we eat.
In summary, villi are essential for the absorption of nutrients in the small intestine, and their location and structure are specifically designed to maximize the efficiency of this process.
