Opening of bile duct before it joins the pancreatic duct is guarded by

Options

A. sphincter of Oddi
B. sphincter of Boyden
C. ampulla of vater
D. pyloric sphincter

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the structure that guards the opening of the bile duct before it joins the pancreatic duct.

2. **Identifying the Options**: The options given are:
- A) Sphincter of Oddi
- B) Sphincter of Boyden
- C) Ampulla of Vater
- D) Pyloric Sphincter

3. **Analyzing the Options**:
- **Sphincter of Oddi**: This sphincter controls the flow of bile and pancreatic juice into the duodenum. It is located at the opening where the bile duct and pancreatic duct meet.
- **Sphincter of Boyden**: This is another name for the Sphincter of Oddi. It is located at the common bile duct before it joins the pancreatic duct.
- **Ampulla of Vater**: This is the structure formed by the joining of the bile duct and pancreatic duct, but it does not guard the opening.
- **Pyloric Sphincter**: This sphincter is located at the junction of the stomach and the small intestine and does not relate to the bile duct or pancreatic duct.

4. **Conclusion**: The correct answer is **Sphincter of Oddi** (or Sphincter of Boyden), as it guards the opening of the bile duct before it joins the pancreatic duct.

5. **Final Answer**: The opening of the bile duct before it joins the pancreatic duct is guarded by the **Sphincter of Oddi**.

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