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

The part of the small intestine that is primarily responsible for nutrient absorption is the jejunum. While all parts of the small intestine contribute to the digestive process, they have different functions and varying degrees of absorptive capacity.

The jejunum, which constitutes the middle section of the small intestine, has specialized structures like villi and microvilli that increase its surface area, allowing for efficient absorption of nutrients such as carbohydrates, proteins, and fats. Most nutrient absorption occurs here due to these adaptations.

The duodenum, the first part of the small intestine, mainly functions in the initial stages of digestion, mixing chyme with bile and pancreatic juices, while the ileum, the final section, continues to absorb nutrients, but is particularly important for the absorption of vitamin B12 and bile salts.

Thus, while the ileum and duodenum play roles in digestion and absorption, the jejunum is the most specialized and effective region for the absorption of nutrients, making it the correct response to focus on when discussing which part primarily handles nutrient absorption.