Which section of the small intestine is most efficient at nutrient absorption?

Which section of the small intestine is most efficient at nutrient absorption?

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

Answer: (B)

Most nutrient absorption happens in the jejunum, the middle section of the small intestine, because its lining provides an enormous surface area and a high capacity for transport. The inner surface is lined with circular folds, on which stand countless villi, and the surfaces of those villi are covered with microvilli. That combination dramatically increases the area available for nutrients to come into contact with the absorbing cells. Add a rich supply of nutrient transporters and brush-border enzymes, and plus strong blood flow to carry absorbed nutrients away, and this region becomes the most efficient at taking up carbohydrates, amino acids, fats, vitamins, and minerals. The other parts play different roles: the duodenum mainly handles digestion and begins absorption, the ileum absorbs specific items like bile acids and vitamin B12, and the cecum is part of the large intestine where water absorption and fermentation occur. So the middle portion of the small intestine is the main workhorse for nutrient uptake.

Most nutrient absorption happens in the jejunum, the middle section of the small intestine, because its lining provides an enormous surface area and a high capacity for transport. The inner surface is lined with circular folds, on which stand countless villi, and the surfaces of those villi are covered with microvilli. That combination dramatically increases the area available for nutrients to come into contact with the absorbing cells. Add a rich supply of nutrient transporters and brush-border enzymes, and plus strong blood flow to carry absorbed nutrients away, and this region becomes the most efficient at taking up carbohydrates, amino acids, fats, vitamins, and minerals. The other parts play different roles: the duodenum mainly handles digestion and begins absorption, the ileum absorbs specific items like bile acids and vitamin B12, and the cecum is part of the large intestine where water absorption and fermentation occur. So the middle portion of the small intestine is the main workhorse for nutrient uptake.