All are actions of CCK except
**Core Concept**
Cholecystokinin (CCK) is a hormone and neurotransmitter that plays a crucial role in the regulation of digestion and appetite. It is released from the duodenum in response to the presence of fat and protein in the small intestine, triggering various physiological responses to facilitate nutrient absorption.
**Why the Correct Answer is Right**
CCK stimulates the contraction of the gallbladder to release bile into the duodenum, which helps in the emulsification and absorption of fats. It also stimulates the release of pancreatic enzymes, including amylase, lipase, and trypsin, which break down carbohydrates, fats, and proteins, respectively. Additionally, CCK has an inhibitory effect on gastric emptying and motility, allowing for proper digestion and absorption of nutrients.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it is not a known action of CCK. CCK does not have a direct effect on the heart rate or blood pressure.
* **Option B:** This option is incorrect because while CCK does stimulate the contraction of the gallbladder, it is not the primary action of CCK. The primary actions of CCK include stimulating pancreatic enzyme secretion and inhibiting gastric emptying.
* **Option C:** This option is incorrect because CCK does stimulate the release of pancreatic enzymes, including gastrin, which stimulates gastric acid secretion. However, CCK itself does not stimulate gastric acid secretion.
**Clinical Pearl / High-Yield Fact**
CCK is often used in the diagnosis of pancreatic insufficiency, as it stimulates pancreatic enzyme secretion and can help identify patients with pancreatic enzyme deficiency.
**Correct Answer: A. This option is incorrect because it is not a known action of CCK. CCK does not have a direct effect on the heart rate or blood pressure.**