What is one function of secretin from S cells?

Secretin, which is secreted by S cells in the small intestine, plays a crucial role in the digestive process, particularly in the regulation of acid levels. One of its primary functions is to help stimulate pancreatic secretion of bicarbonate. This bicarbonate is vital because it neutralizes stomach acids that enter the small intestine, creating an optimal pH for digestive enzymes to function effectively. By ensuring that the intestinal environment is not too acidic, secretin ultimately contributes to the proper digestion and absorption of nutrients.

In contrast to secretin's role in stimulating bicarbonate secretion, other options do not align with its functions. For example, the stimulation of gastric acid secretion is typically regulated by different hormones, such as gastrin. Similarly, gastric emptying is influenced by various factors, including other hormones and neural signals, rather than secretin directly promoting this process. Secretin also does not have a direct role in appetite stimulation or food intake; those processes are largely governed by other hormones such as ghrelin and leptin.