Which part of the small intestine is primarily responsible for nutrient absorption?

The small intestine consists of three distinct sections: the duodenum, jejunum, and ileum. Each section plays a role in the digestive process. However, the primary site for nutrient absorption is the jejunum, followed by the ileum, which also participates in absorbing certain nutrients and minerals.

While the duodenum is critical for the initial stages of digestion, where gastric juices mix with chyme, it is not the main area where the bulk of nutrient absorption occurs. The jejunum is specially adapted for this function due to its extensive surface area and specialized structures called villi and microvilli, which increase absorption efficiency. The ileum continues this absorption process, particularly for vitamin B12 and bile salts.

Thus, focusing solely on the jejunum clarifies that while all parts contribute in varying degrees, the jejunum is chiefly responsible for nutrient absorption, making the inclusive answer that designates all sections as equally responsible inaccurate in the context of primary nutrient absorption. The emphasis should be placed on understanding the unique roles of each section rather than suggesting they all have the same level of responsibility in this specific process.