What is the correct order of segments in the small intestine?

What is the correct order of segments in the small intestine?

• A. Duodenum, Jejunum, Ileum
• B. Ileum, Duodenum, Jejunum
• C. Jejunum, Ileum, Duodenum
• D. Duodenum, Ileum, Jejunum

Answer: (A)

The small intestine processes chyme through three consecutive sections, each specialized for digestion and absorption. It starts with the duodenum, where chyme from the stomach mixes with bile and pancreatic juice to begin chemical digestion and neutralize stomach acid. Next comes the jejunum, the primary site of nutrient absorption thanks to its large surface area created by folds, villi, and microvilli. Finally, the ileum completes absorption, especially of bile acids and vitamin B12, and contains lymphoid tissue that helps with immune function. Since chyme moves in that direction, the correct order is the duodenum, then the jejunum, and then the ileum.

The small intestine processes chyme through three consecutive sections, each specialized for digestion and absorption. It starts with the duodenum, where chyme from the stomach mixes with bile and pancreatic juice to begin chemical digestion and neutralize stomach acid. Next comes the jejunum, the primary site of nutrient absorption thanks to its large surface area created by folds, villi, and microvilli. Finally, the ileum completes absorption, especially of bile acids and vitamin B12, and contains lymphoid tissue that helps with immune function. Since chyme moves in that direction, the correct order is the duodenum, then the jejunum, and then the ileum.