Secretin is released from S cells of the duodenum in response to low duodenal pH. Its primary action on the pancreas is to:

• A Stimulate secretion of enzyme-rich pancreatic juice
• B Inhibit gastric acid secretion and increase gastrin release
• C Stimulate pancreatic glucagon secretion
• D Stimulate secretion of bicarbonate-rich pancreatic juice to neutralize duodenal acid ✓

Explanation

Secretin acts on pancreatic ductal cells via cAMP-mediated pathways to produce a large volume of bicarbonate-rich, enzyme-poor juice. This alkaline secretion raises the duodenal pH toward neutral, which is essential for pancreatic enzyme activity (optimal pH 7-8) and protects the duodenal mucosa. CCK, not secretin, stimulates enzyme-rich secretion from acinar cells. Secretin also inhibits gastric acid and gastric emptying.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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