The back flow of faecal matter from the large intestine into the small intestine is prevented by the presence of

Options

A. epiglottis
B. sphincter of Oddi closes the hepato-pancreatic duct
C. ileo-caecal valve
D. gastro-oesophageal sphincter.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the mechanism that prevents the backflow of fecal matter from the large intestine into the small intestine.

2. **Identifying the Structures**: We need to consider the various structures involved in the digestive system that could potentially prevent this backflow. The options provided include:
- Epiglottis
- Sphincter of Oddi
- Ileocecal valve
- Gastroesophageal sphincter

3. **Analyzing Each Option**:
- **Epiglottis**: This structure is located at the entrance of the larynx and prevents food from entering the trachea during swallowing. It does not play a role in the connection between the small and large intestines.
- **Sphincter of Oddi**: This sphincter controls the flow of bile and pancreatic juice into the duodenum but is not involved in preventing backflow between the small and large intestines.
- **Ileocecal Valve**: This valve is located between the ileum (the last part of the small intestine) and the cecum (the first part of the large intestine). Its primary function is to prevent the backflow of fecal matter from the large intestine into the small intestine.
- **Gastroesophageal Sphincter**: This sphincter is located between the esophagus and the stomach and does not relate to the small and large intestines.

4. **Conclusion**: Based on the analysis, the structure that prevents the backflow of fecal matter from the large intestine into the small intestine is the **ileocecal valve**.

**Final Answer**: The backflow of fecal matter from the large intestine into the small intestine is prevented by the presence of the **ileocecal valve**.

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