What is the primary function of the small intestine?

The primary function of the small intestine is to absorb nutrients. After food is digested in the stomach, it moves into the small intestine, where it is mixed with digestive enzymes and bile that help break down the food into smaller, absorbable components. The walls of the small intestine are lined with tiny, finger-like projections called villi, which increase the surface area for absorption. This structure allows for efficient uptake of nutrients, such as amino acids, fatty acids, and simple sugars, directly into the bloodstream, which then transports them to cells throughout the body for energy, growth, and repair.

While digestion does occur in the small intestine, the primary role is nutrient absorption rather than digestion itself. Other options, like storing waste, are functions related to the large intestine, and producing bile is a function of the liver rather than the small intestine. Understanding the distinct roles of different parts of the digestive system helps clarify the small intestine's crucial role in overall nutrition and health.