This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal System, Subject name: Physiology
Common for CCK and Gastrin: 
Select and explain. 
A. Trophic action, B. CCK A receptor, C. Increases gastric emptying, D. Secretion is stimulated by fatty acids
A: Trophic action
Answer: A: Trophic action 
Explanation: Gastrin stimulates mucosal growth of the stomach and small and large intestines (trophic action). CCK exes a trophic effect on the pancreas. Gastrin secretion is increased by the presence of the products of protein digestion in the stomach, paicularly amino acids. The secretion of CCK is increased by contact of the intestinal mucosa with the products of digestion, paicularly peptides and amino acids, and also by the presence in the duodenum of fatty acids containing more than 10 carbon atoms. Gastrin increases while CCK decreases gastric emptying.