Which part of body secretes the hormone secretin?

Options

A. Stomach
B. Oesophagus
C. Ileum
D. Duodenum

Answer

**Step-by-Step Solution:**

1. **Understanding Secretin**: Secretin is a hormone that plays a crucial role in the digestive process. It is primarily involved in regulating the pH of the small intestine.

2. **Identifying the Source**: Secretin is secreted by specialized cells known as S cells. These cells are classified as interoendocrine cells, which are related to the gastrointestinal tract.

3. **Location of S Cells**: The S cells that secrete secretin are located in the small intestine, specifically in the duodenum, which is the first part of the small intestine.

4. **Function of Secretin**: Once secretin is secreted into the bloodstream, it travels to the pancreas. Here, it stimulates the pancreas to release bicarbonate ions (HCO3-), which help neutralize the acidic chyme coming from the stomach, creating a more alkaline environment in the small intestine.

5. **Conclusion**: Therefore, the part of the body that secretes the hormone secretin is the duodenum of the small intestine.

**Final Answer**: The hormone secretin is secreted by the duodenum in the small intestine.

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