Question

What are the 3 phases of gastric secretion?

Answer 1

Gastric secretion:

1. The gastric mucosa secretes 1.2 to 1.5 liters of gastric juice per day.
2. Gastric juice initiates digestion, and converts the gastric materials to a semiliquid mass called chyme, thus preparing it for further digestion in the small intestine.
3. Gastric juice is a variable mixture of water, hydrochloric acid, electrolytes, and organic substances (mucus, pepsins, and protein).
4. The physiologic stimulation of acid secretion has classically been divided into three interrelated phases: cephalic, gastric, and intestinal.

• The cephalic phase of gastric secretion – The cephalic phase is activated by the sense of thought, taste, smell, the sight of food, and swallowing. It is mediated mostly by cholinergic/vagal mechanisms.
• The gastric phase of gastric secretion – is mediated by the vagus nerve and by the release of gastrin.
• The intestinal phase of gastric secretion – involves complex stimulatory and inhibitory processes.