The portion of the small intestine that attaches to the cecum is the
A) haustrum.
C) ileum.
D) duodenum.
E) jejunum.
The correct answer and explanation is :
The correct answer is D) duodenum.
Explanation:
The duodenum is the first section of the small intestine, immediately following the stomach. It plays a critical role in digestion by receiving partially digested food (chyme) from the stomach and mixing it with digestive enzymes and bile.
1. Structure & Location:
The duodenum is a C-shaped, approximately 25–30 cm (10–12 inches) long structure that curves around the head of the pancreas. It is the shortest but most crucial segment of the small intestine.
2. Function in Digestion:
The duodenum serves as a primary site for chemical digestion. It receives:
- Bile from the liver and gallbladder (via the common bile duct) to help digest fats.
- Pancreatic enzymes (via the pancreatic duct) that break down proteins, carbohydrates, and fats.
- Secretions from the intestinal glands that further aid in digestion and neutralize stomach acid.
3. Neutralization of Acid:
Since the stomach secretes highly acidic gastric juice, the duodenum must neutralize it before it moves further into the intestines. The Brunner’s glands in the duodenal wall secrete an alkaline mucus that helps protect the lining from stomach acid.
4. Absorption in the Duodenum:
While the jejunum (option E) is primarily responsible for nutrient absorption, some absorption occurs in the duodenum, including:
- Iron, calcium, and magnesium
- Simple sugars, amino acids, and small peptides
Conclusion:
The duodenum is the first and most important segment of the small intestine for digestion, whereas the jejunum primarily absorbs nutrients. Therefore, the correct answer is D) duodenum.
