Question

How long is the duodenum? What is its primary job?

Answer 1

Hint: The first part of the small intestine located between the stomach and the middle part of the small intestine in higher vertebrates is called the duodenum.

Complete answer:
The long, narrow, coiled, and folded tube running in the gastrointestinal tract, from the stomach to the large intestine in higher vertebrates, is called the small intestine. It has three main parts- the duodenum, the jejunum, and the ileum. The major work of digestion occurs here. In humans, the length of the small intestine is approximately 22 feet or seven meters.
Duodenum is the first section of the small intestine connecting the stomach with the jejunum. It is the shortest part of the small intestine and has a C-shaped or horse-shoe shaped structure. The average length of the duodenum in humans is 25 to 38 cm or 10 to 15 inches. It has four major anatomical parts- the superior part or the cap, the descending part, the inferior part, and the ascending part. It lies in the upper abdomen near the head of the pancreas, just beneath the stomach. It is connected to the stomach through a pyloric sphincter. It is also connected to the liver, gallbladder, and pancreas.

The duodenum receives partially digested food from the stomach called Chyme. Its major function is to process the chyme and absorb the nutrients from it. It also neutralizes stomach acidity by secreting an alkaline fluid along with the intestinal organs- gallbladder, liver, and pancreas. The juices along with bile enter the pancreas through ducts and neutralize the stomach acids.

These secretions also act on the Chyme along with some enzymes and lead to its breakdown. The chyme is broken into simpler forms where the nutrients can be easily absorbed from them. The absorption of iron and a few other vitamins, calcium, and amino acids also occur here. The processed food is moved to the jejunum for the further absorption of nutrients. They also regulate the emptying of the stomach.

Note: The second portion of the small intestine is the Jejunum which measures approximately 2.5m. Its main function is to absorb sugars, amino acids, and fatty acids. The third part of the small intestine is Ileum and is around 3 meters in length. It majorly absorbs Vitamin B12 and bile acids, and all the other important substances that were earlier not absorbed.