The Physiology of Gastric Secretions 5
February 1st 2010 16:34
Phases of Gastric Secretion
Gastric secretion involves three phases: cephalic, gastric, and intestinal phase. Cephalic phase occurs even before food enters the stomach. It results from the sight, smell, thought, or taste of food. “Neurogenic signals that cause the cephalic phase of gastric secretion can originate in the cerebral cortex or in the appetite centers of the amygdala or hypothalamus. They are transmitted through the dorsal motor nuclei of the vagi and then through the vagus nerves to the stomach (Guyton and Hall, 2000).” The cephalic phase accounts to 20 percent of gastric secretion.
The gastric phase accounts for 70 percent of gastric secretion. Once food enters the stomach, it excites the vagovagal reflexes, the local enteric reflexes, and the gastrin mechanism.
The presence of food in the upper part of the small intestine can cause the stomach to further release gastric juice. This is caused by small amount of gastrin secreted in the mentioned site of the small intestine.
Gastric secretion involves three phases: cephalic, gastric, and intestinal phase. Cephalic phase occurs even before food enters the stomach. It results from the sight, smell, thought, or taste of food. “Neurogenic signals that cause the cephalic phase of gastric secretion can originate in the cerebral cortex or in the appetite centers of the amygdala or hypothalamus. They are transmitted through the dorsal motor nuclei of the vagi and then through the vagus nerves to the stomach (Guyton and Hall, 2000).” The cephalic phase accounts to 20 percent of gastric secretion.
The presence of food in the upper part of the small intestine can cause the stomach to further release gastric juice. This is caused by small amount of gastrin secreted in the mentioned site of the small intestine.
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