How Long is the Small Intestine

The small intestine in the human body is explained here. Also provided are some diseases which affect this organ.
Bodytomy Staff
Last Updated: Aug 7, 2018
digestive system
The human digestive system begins from the mouth and ends at the anus.
The ingested food passes through the pharynx, esophagus, stomach, and the intestines. The human intestine is divided into two major parts; the small and the large intestine.
How Long is the Small Intestine in Humans
The small intestine, also known as small bowel, is one of the longest organs of the digestive system. As it has a lesser diameter than the large intestine, it is known as the small intestine.
The length of the small intestine is about 6 to 7 meters (20 to 23 feet) when stretched out. This organ is also divided into 3 sections. These include the duodenum, jejunum, and ileum. Let us go through the details of the length according to the parts of the small intestine.
Duodenum
The junction where the stomach meets the small intestine is called the duodenum. This part is about 25 cm. in length, and has a 'C' shape. Its function includes receiving the partially digested food from the stomach. The pH is alkaline that helps in neutralizing the acidic pH of the partially digested food.
The gallbladder secretes the bile juice and other digestive enzymes into the duodenum. The digested food mixture is covered in mucus produced by other glands, to help it pass through the small intestine. The major part of digestion takes place in the duodenum. The proteins, fats, and carbohydrates are also digested in the part.
Jejunum and Ileum
Jejunum is about 1 to 2 meters long and is present in the mid-section of small intestine. Ileum is about 2 to 4 meters in length and is the last part of the intestine. This coiled tube contains small finger like projections called the 'villi'. They help in increasing surface area of the intestine, thus increasing the absorption capacity of more nutrients.
The final digestion of the food occurs in this region. Smaller molecules like amino acids, fatty acids, and glucose are also broken down in this section. Vitamins, minerals, salt, as well as water is absorbed in this part. These vital nutrients are then secreted into the bloodstream and the liver.
Comparison of the Two Intestines
Although called the large intestine, it is just about 1.5 meters (5 feet) in length. Thus, as compared to the length of the small intestine, the larger one is quite small. The function of the large intestine is to digest the food, which has not been broken down in the small intestine.
This includes breakdown of fibers, digestion of protein molecules, cellulose from plant sources, and water. The beneficial bacteria present in this part, helps in breakdown of several organic molecules. The waste or feces are stored in the large intestine, till they are eliminated through the anus.
Small Intestine Problems
Few diseases of the small intestine are as follows:
  • Small intestine blockage/obstruction
  • Small intestine cancer
  • Crohn's disease
  • Celiac disease
  • Human tapeworm infection
  • Inguinal hernia