What is the main role of the small intestine in the digestive system?

The small intestine plays a critical role in the digestive system primarily by absorbing nutrients into the bloodstream. Once food leaves the stomach, it enters the small intestine, where the majority of digestion and nutrient absorption occurs. The walls of the small intestine are lined with tiny, finger-like projections called villi and microvilli, which increase the surface area available for absorption.

As food is digested, nutrients such as amino acids, fatty acids, simple sugars, vitamins, and minerals are absorbed through these projections directly into the bloodstream, allowing the body to utilize these essential components for energy, growth, and cellular repair. While the small intestine also plays a part in breaking down proteins and fats with the help of enzymes and bile, its primary and most important function is nutrient absorption. This distinct role sets it apart from other parts of the digestive system, which have different functions such as the production of bile in the liver or waste elimination through the large intestine.