State the pH nature of the contents of the stomach and the small intestine.

State the pH nature of the contents of the stomach and the small intestine.

• A. Stomach alkaline; Small intestine acidic
• B. Stomach acidic; Small intestine alkaline
• C. Stomach neutral; Small intestine alkaline
• D. Stomach acidic; Small intestine neutral

Answer: (B)

Digestion involves a big pH shift along the gut. The stomach produces strong gastric acid, so its contents are very acidic, with a pH around 1–3. When chyme enters the small intestine, bicarbonate-rich secretions from the pancreas and bile neutralize the acid, raising the pH to roughly neutral/alkaline (about 7–8). This alkaline environment is essential for the enzymes in the intestine to work and to protect the intestinal lining. So the correct description is that the stomach contents are acidic and the small intestine contents are alkaline.

Digestion involves a big pH shift along the gut. The stomach produces strong gastric acid, so its contents are very acidic, with a pH around 1–3. When chyme enters the small intestine, bicarbonate-rich secretions from the pancreas and bile neutralize the acid, raising the pH to roughly neutral/alkaline (about 7–8). This alkaline environment is essential for the enzymes in the intestine to work and to protect the intestinal lining. So the correct description is that the stomach contents are acidic and the small intestine contents are alkaline.