Intestinal juices are secreted by the lining of which organ?

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

Answer: (B)

Intestinal juice is produced by glands in the mucosal lining of the small intestine, specifically in the duodenum and the rest of the small intestine. This watery fluid contains brush-border enzymes such as disaccharidases, peptidases, and other enzymes that finalize digestion right at the surface of the intestinal wall, helping break down sugars and proteins into absorbable units as chyme passes through. The small intestine is the main site for digestion and absorption, so it makes sense that its lining supplies this digestive fluid. In contrast, the stomach produces gastric juice for early digestion, the liver makes bile for fat emulsification, and the esophagus mainly provides protective mucus, not intestinal juice.