What are the phases of gastric acid secretion and their percentage contributions?

The correct choice establishes a clear understanding of the phases of gastric acid secretion, which are categorized into three distinct phases: cephalic, gastric, and intestinal, each contributing to the overall secretion of gastric acid.

The cephalic phase, which accounts for approximately 30% of gastric acid secretion, is primarily triggered by the sight, smell, taste, or thought of food. This phase involves the brain signaling the stomach to prepare for digestion, leading to increased acid production even before food enters the stomach.

The gastric phase contributes around 60% to gastric acid secretion and is initiated when food actually enters the stomach. The presence of food stimulates the stomach lining to produce more acid and enzymes through both local and neural responses, significantly elevating the secretion of gastric juices.

The intestinal phase makes a smaller contribution at about 10%, representing the final stage of gastric acid secretion. It is stimulated by the presence of chyme (partially digested food) in the small intestine, which leads to further modulation of gastric secretions as digestive processes transition from the stomach to the intestines.

This breakdown reflects the physiological processes involved in digestion and how they are regulated, illustrating that the cephalic phase serves as an anticipatory response, while the gastric phase is