In the human digestive system, which section is correctly identified as the duodenum?

• A. The last section of the large intestine before the rectum
• B. The first part of the small intestine immediately following the stomach
• C. The muscular tube connecting the mouth to the stomach
• D. The pouch-like structure at the beginning of the large intestine

Answer: (B)

Verified step by step guidance

1. Understand the anatomy of the human digestive system: The digestive system is composed of several organs, including the stomach, small intestine, and large intestine. Each section has a specific role in digestion and nutrient absorption.
2. Define the duodenum: The duodenum is the first part of the small intestine. It is located immediately after the stomach and plays a critical role in digestion by receiving chyme (partially digested food) from the stomach and mixing it with digestive enzymes and bile.
3. Eliminate incorrect options: Review the provided options and identify which ones do not describe the duodenum. For example, the last section of the large intestine before the rectum refers to the sigmoid colon, not the duodenum. Similarly, the muscular tube connecting the mouth to the stomach is the esophagus, and the pouch-like structure at the beginning of the large intestine is the cecum.
4. Confirm the correct option: The correct description of the duodenum is 'The first part of the small intestine immediately following the stomach.' This matches the anatomical location and function of the duodenum.
5. Summarize the reasoning: The duodenum is distinct from other parts of the digestive system due to its position and role in digestion. By process of elimination and understanding its function, the correct answer is identified as the first part of the small intestine immediately following the stomach.