What is a potential consequence of pancreatic HCO3- secretion being absent?

The absence of pancreatic bicarbonate (HCO3-) secretion can significantly impact the pH balance in the small intestine. Bicarbonate plays a critical role in neutralizing the acidic chyme that comes from the stomach into the duodenum. When this neutralization does not occur due to insufficient bicarbonate secretion, the acidic environment cannot be adequately balanced.

This leads to increased acidity in the small intestine, potentially resulting in conditions such as metabolic acidosis. Conversely, the mistaken understanding that the absence of bicarbonate secretion could lead to metabolic alkalosis is inaccurate. Metabolic alkalosis typically arises from excessive bicarbonate levels or loss of acid, not from a deficiency. Therefore, the consequences of lacking HCO3- secretion include increased blood acidity, rather than alkalosis.

Thus, when pancreatic bicarbonate secretion is absent, the immediate effect is the inability to buffer gastric acid properly, resulting in higher acidity levels in the blood, making the metabolic acidosis answer more accurate.