From what part of the digestive system does digested food enter the blood?

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

Answer: (C)

Nutrients get into the bloodstream mainly in the small intestine. Its lining is folded into villi and microvilli, which massively increase surface area so nutrients can cross into tiny blood vessels (capillaries) inside the villi. Once in the capillaries, these nutrients are carried away by the blood to body cells. While fats are also absorbed, they initially enter the lymphatic system via lacteals in the villi, then join the bloodstream later. The other parts of the digestive tract have different roles: the esophagus mainly transports food, the stomach digests and churns with limited absorption, and the large intestine mainly absorbs water.