The small intestine is designed to absorb digested food efficiently through several structural adaptations. Its inner surface has millions of tiny finger- like projections called villi, which greatly increase the surface area for absorption. Each villus contains a network of blood capillaries and a lymph vessel (lacteal) that help transport absorbed nutrients into the bloodstream and lymphatic system. Additionally, the epithelial cells lining the villi have microvilli, further increasing the surface area and enhancing nutrient absorption. The walls of the small intestine also secrete intestinal juices that complete digestion, making nutrients like glucose, amino acids, and fatty acids small and water-soluble for easier absorption into the blood.
Key Design Features for Absorption
- Villi: Finger-like projections increasing surface area.
- Microvilli: Smaller projections on villi cells, further increasing surface area.
- Rich Blood Supply: Capillaries within villi transport absorbed nutrients.
- Lacteal: Lymph vessel in villi absorbs fatty acids and glycerol.
- Digestive Enzymes: Intestinal juices aid in breaking down food into absorbable molecules.
These features collectively ensure maximum absorption efficiency of digested food in the small intestine.
