Your patient has a retractable gastric peptic ulcer and has had a gastric vagotomy. Which factor increases as a result of vagotomy?
A. Peristalsis
B. Gastric acidity
C. Gastric motility
D. Gastric pH
Correct Answer: D. Gastric pH
If the vagus nerve is cut as it enters the stomach, gastric acid secretion is decreased, but intestinal motility is also decreased and gastric emptying is delayed. Because gastric acids are decreased, gastric pH increases. The postoperative complications of truncal vagotomy are well documented. Resection of the vagal nerve trunks above the celiac and hepatic branches (differentiates TV versus SV) leads to parasympathetic denervation of the pylorus, liver, biliary tree, pancreas, and small and large intestines.
Option A: The stomach loses the vagally mediated receptive relaxation. This leads to an increased intragastric pressure causing an increased emptying of liquids. The pylorus does not relax effectively, and a decrease in solid food emptying is seen.
Option B: Gastrin is secreted by the G cells that are mainly located in the stomach antrum and pylorus. Acetylcholine is released in response to parasympathetic stimulation, which travels in the fibers of the vagus nerves. Histamine is released by the enterochromaffin-like cells.
Option C: Gastric phase begins once food enters the stomach. It is stimulated by proximal stomach distension (vagally mediated). It is absent in patients with a vagotomy. The gastric phase is stimulated by amino acids and peptides, leading to G cell activation. It accounts for 60% of total acid production.
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