What are the 3 major regions of the small intestine?

What are the 3 major regions of the small intestine?

• A. Duodenum, Jejunum, Ileum
• B. Duodenum, Jejunum, Cecum
• C. Jejunum, Ileum, Colon
• D. Duodenum, Ileum, Jejunum

Answer: (A)

The small intestine has three regions in sequence: the duodenum, the jejunum, and the ileum. The duodenum is the first segment where chyme mixes with bile and pancreatic juices. The jejunum is the middle portion where most nutrient digestion and absorption occur. The ileum is the final segment where absorption continues and bile acids and vitamin B12 are primarily reabsorbed. The other options mix in parts of the large intestine (such as the cecum or colon) or place the segments in the wrong order, so they don’t fit the small intestine’s standard arrangement.

The small intestine has three regions in sequence: the duodenum, the jejunum, and the ileum. The duodenum is the first segment where chyme mixes with bile and pancreatic juices. The jejunum is the middle portion where most nutrient digestion and absorption occur. The ileum is the final segment where absorption continues and bile acids and vitamin B12 are primarily reabsorbed. The other options mix in parts of the large intestine (such as the cecum or colon) or place the segments in the wrong order, so they don’t fit the small intestine’s standard arrangement.