Cholecystokinin is secretion of

Options

A. Duodenum that causes contraction of gall bladder
B. Goblet cells of ileum the stimulate secretion of succus entericus
C. Liver and controls secondary sex characters
D. Stomach that stimulates pancreas to release juice

Answer

**Step-by-Step Solution:**

1. **Understanding Cholecystokinin (CCK)**: Cholecystokinin is a peptide hormone that plays a crucial role in digestion. It is primarily involved in the digestion of fats and proteins.

2. **Location of Secretion**: CCK is secreted by the I cells located in the lining of the duodenum, which is the first part of the small intestine.

3. **Stimuli for Secretion**: The secretion of CCK is stimulated by the presence of chyme (partially digested food) in the duodenum, particularly when it contains fatty acids and amino acids.

4. **Function of Cholecystokinin**: Once released into the bloodstream, CCK causes the gallbladder to contract, leading to the release of bile into the small intestine. Bile is essential for the emulsification and digestion of fats.

5. **Evaluating the Options**:
- **Option A**: Duodenum that causes contraction of gallbladder - This is correct.
- **Option B**: Goblet cells of ileum that stimulate secretion of saccus antericus - This is incorrect.
- **Option C**: Liver and control secondary sex characters - This is incorrect.
- **Option D**: Stomach that stimulates pancreas to release juices - This is incorrect.

6. **Conclusion**: The correct answer is **Option A**: Cholecystokinin is a secretion of the duodenum that causes contraction of the gallbladder.

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