Which secretions mix with chyme in the small intestine along with intestinal juices?

• A. Pancreatic juices and bile salts
• B. Saliva and mucus
• C. Gastric acid and pepsin
• D. Mucus and bicarbonate only

Answer: (A)

When chyme leaves the stomach and enters the small intestine, it must be mixed with secretions that neutralize its acidity and continue digestion. The major additions in the small intestine are pancreatic juice and bile. Pancreatic juice supplies digestive enzymes (amylase, lipase, proteases) and a large amount of bicarbonate to raise the pH, protecting the intestinal lining and creating the right environment for enzymes to work. Bile salts from the liver/gallbladder emulsify fats, increasing the surface area for fat digestion.

Saliva and gastric secretions don’t play a significant role in mixing with chyme in the small intestine. Gastric acid and pepsin function in the stomach and are largely neutralized before chyme reaches the intestine. Mucus is present along the intestinal tract and bicarbonate is produced, but the key additions that actively mix with chyme to finish digestion are pancreatic juice and bile.