How Long is the Small Intestine

The human digestive system begins from the mouth and ends at the anus. The food passes through the pharynx then the esophagus, stomach and then the intestines. This is where things tend to get a bit complicated. The intestine is divided into two major parts; the small intestine and the large intestine. Have you ever wondered why is the small intestine called small? When, you will find out the length of the small intestine in the following paragraphs, you will be quite surprised. Let us go into the details of how long is small intestine in humans.

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. I am sure you must be wondering why is it called a small intestine, when it is actually the longest organ. The reason is the anatomy of the small intestine, that is, smaller in diameter than the large intestine.

The length of small intestine is about 6 to 7 meters (20 to 23 feet) when stretched out. Just imagine, a long tube that is placed inside your abdomen. And not just the length of the small intestine is over 6 feet long, but it is also divided into 3 sections. These include the duodenum, jejunum and ileum. Let us go into the details of the length according to the parts of the small intestine. We shall also go into the small intestine function as we go through each individual part.

Duodenum
The junction where the stomach meets the small intestine is actually the duodenum. Thus, making it the first part of small intestine. The duodenum is about 25 cm in length and has a C shape. The duodenum function includes receiving the partially digested food from the stomach. The pH of the duodenum is alkaline that helps in neutralizing the acidic pH of the partially digested food. The gallbladder secretes 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 digested in the duodenum.

Jejunum and Ileum
The jejunum is about 1 to 2 meters long and present in mid section of the small intestine. The ileum is about 2 to 4 meters in length. The last part of the small intestine is the ileum. This coiled tube contains small finger like projections called the 'villi'. This helps in increasing the surface area of the intestine and thus, helps in absorbing more nutrients. The final digestion of the food occurs in this region. The small molecules like amino acids, fatty acids and glucose are broken down in this region. Vitamins, minerals, salt as well as water is absorbed here. These vital nutrients are 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 large intestine is very small. The large intestine function is to digest the food that has not been digested in the small intestine. This includes breakdown of fibers, digestion of protein molecules, cellulose from plant sources and water. The beneficial bacteria present in large intestine, help in breakdown of these molecules. The waste or feces are stored in the large intestine, till they are eliminated through the anus.

Small Intestine Problems

There are many small intestine problems that may affect the overall digestive health. Some of the small intestine diseases are as follows:

• Small intestine blockage / obstruction
• Small intestine cancer
• Crohn's disease
• Celiac disease
• Human tapeworm infection
• Inguinal hernia

The length of the small intestine is about 6 to 7 meters and the large intestine is about 1.5 meters long. The total length of the intestines in the human digestive system is about 7.5 to 8.5 meters.