Fat in the duodenum lumen: (A) Stimulates gall bladder contraction, (B) Inhibits gall bladder contraction, (C) Inhibits CCK secretion, (D) Releases secretin
Answer is A. Products of fat digestion (long chain fatty acids with more 10 carbon atoms) in the duodenum increase the secretion of CCK, the most potent hormone causing gallbladder contraction.