Secretin and cholecystokinin are digestive hormones. These are secreted by:

Options

A. Oesophagus
B. Ileum
C. Duodenum
D. Pyloric stomach

Answer

**Step-by-Step Solution:**

1. **Understanding Secretin and Cholecystokinin**: Secretin and cholecystokinin are both hormones involved in the digestive process. They play crucial roles in regulating the functions of the digestive system.

2. **Identifying the Source of Secretion**: These hormones are secreted by specific parts of the gastrointestinal tract. The question asks where these hormones are secreted.

3. **Locating the Correct Anatomical Site**: The primary site of secretion for both secretin and cholecystokinin is the duodenum, which is the first part of the small intestine. This is where they are released in response to the presence of acidic chyme and fatty acids.

4. **Functions of the Hormones**:
- **Secretin**: It stimulates the pancreas to release bicarbonate-rich pancreatic juice, which helps neutralize stomach acid in the small intestine.
- **Cholecystokinin (CCK)**: It stimulates the gallbladder to release bile and also promotes the secretion of pancreatic enzymes, aiding in the digestion of fats and proteins.

5. **Conclusion**: Therefore, the correct answer to the question is that secretin and cholecystokinin are secreted by the duodenum.

**Final Answer**: Secretin and cholecystokinin are secreted by the duodenum.

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