Final answer:
Bicarbonate ions produced by the pancreas neutralize the acid contents in the duodenum to ensure a suitable environment for nutrient absorption and enzyme function. Option A is correct.
Step-by-step explanation:
Bicarbonate ions (HCO₃) from the pancreas neutralize the acid contents in the duodenum. When food leaves the stomach, it is mixed with chyme, which is highly acidic. To make sure the small intestine's environment is suitable for nutrient absorption and further digestion, the pancreas secretes an alkaline bicarbonate solution into the duodenum.
This bicarbonate neutralizes the acidity of the chyme, allowing digestive enzymes to function properly and protect the intestinal lining from damage. The hormones secretin and cholecystokinin (CCK) stimulate the pancreas to release these bicarbonate ions as part of the digestive process.
In the duodenum, the pancreas secretes bicarbonate ions to neutralize the acid contents. When chyme, the acidic food from the stomach, enters the duodenum, a hormone called secretin stimulates the pancreas to produce an alkaline bicarbonate solution. This bicarbonate solution helps neutralize the acidity of the chyme and creates a more favorable environment for digestion in the small intestine.