Which part of the digestive system absorbs nutrients into the bloodstream?

• A. Stomach
• B. Small intestine
• C. Esophagus
• D. Liver

Answer: (B)

Nutrients enter the bloodstream mainly through the small intestine. Its lining is heavily folded into villi and microvilli, giving a huge surface area for absorption. Tiny blood vessels in the villi take up amino acids and simple sugars that have been digested, delivering them into the bloodstream to be carried around the body. Fats are absorbed a bit differently, entering the lymphatic system first, but they eventually reach the bloodstream as well.

The stomach primarily digests and churns food and only absorbs small amounts of water and some substances. The esophagus is just a passageway with no digestive absorption. The liver processes nutrients after they enter the bloodstream but does not absorb them directly from the gut.