A common duct that opens into duodenum and is guarded by spincter of Oddi is formed by joining of

Options

A. Cystic duct+pancreatic duct
B. Main pancreatic duct+common bile duct
C. Cystic duct+common bile duct
D. Common bile duct+ duct of santorini

Answer

To solve the question regarding the common duct that opens into the duodenum and is guarded by the sphincter of Oddi, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Anatomy**: The duodenum is the first part of the small intestine, and it receives secretions from the liver and pancreas. The common duct that opens into the duodenum is crucial for digestion.

2. **Identify the Ducts Involved**: The question mentions several ducts:
- Cystic duct
- Pancreatic duct (also known as the main pancreatic duct or duct of Wirsung)
- Common bile duct
- Duct of Santorini

3. **Trace the Pathway**:
- The **right and left hepatic ducts** combine to form the **common hepatic duct**.
- The **cystic duct** from the gallbladder joins the common hepatic duct to form the **common bile duct**.
- The **common bile duct** then merges with the **main pancreatic duct**.

4. **Formation of the Hepatopancreatic Duct**: The junction of the common bile duct and the main pancreatic duct forms the **hepatopancreatic duct**, which opens into the duodenum.

5. **Sphincter of Oddi**: This duct is guarded by the sphincter of Oddi, which controls the flow of bile and pancreatic juice into the duodenum.

6. **Conclusion**: Therefore, the common duct that opens into the duodenum and is guarded by the sphincter of Oddi is formed by the joining of the **main pancreatic duct and the common bile duct**.

### Final Answer:
The answer is **option B: main pancreatic duct and common bile duct**.

---