What are the three phases of gastric secretion in the digestive system?

• A. Oral, esophageal, and gastric phases
• B. Ingestion, digestion, and absorption phases
• C. Buccal, pharyngeal, and esophageal phases
• D. Cephalic, gastric, and intestinal phases

Answer: (D)

Verified step by step guidance

1. Understand that gastric secretion is a complex process regulated by neural and hormonal factors, and it occurs in three distinct phases.
2. The first phase is the Cephalic phase, which is triggered by the sight, smell, taste, or thought of food. This phase involves the central nervous system, where the brain sends signals to the stomach to prepare for digestion by increasing gastric juice secretion.
3. The second phase is the Gastric phase, which begins when food enters the stomach. This phase is stimulated by the distension of the stomach and the presence of peptides and amino acids. It involves both neural reflexes and the release of gastrin, a hormone that further stimulates gastric juice production.
4. The third phase is the Intestinal phase, which starts when partially digested food enters the small intestine. This phase involves hormonal responses that initially stimulate gastric secretion but eventually inhibit it to slow down gastric emptying and allow for proper digestion and absorption in the intestines.
5. Recognize that these phases work together to ensure that gastric secretion is appropriately regulated, optimizing the digestive process and nutrient absorption.