Small Intestine

The small intestine is part of the digestive system. It is a winding tube averaging about 20 feet long in adults. It is called “small” because it is only about an inch in diameter. Its function is the main reason our body gets nutrients from the food we eat.

Fun Facts

● The small intestine is an organ and is also referred to as bowels.
● When you eat, the food goes down your esophagus and into your stomach. Juices in your stomach break the food down into a liquid. This liquid then enters the small intestine.
● The small intestine is so long that it has three parts. They are called; the duodenum, the ileum, and the jejunum. The first two are shorter and prepare the food for the last one, where most of the nutrients are absorbed.
● The small intestine is made of muscles. The outer layer of muscle is thin and smooth and squeezes and relaxes to keep the food moving in one direction. The inner layer of muscle is thick and circular with many folds and villi, which are like little fingers. These folds and villi make the surface area actually very large.
● The villi are connected to blood vessels so that the nutrients from our food and drink can be carried to where they are needed.
● The small intestine is where most of the work of digestion happens. The juices, or enzymes, from the small intestine work with enzymes from the liver and pancreas to absorb nutrients into our bloodstream.
● The job of the small intestine is to break down the food so that our bodies can absorb all the vitamins, minerals, carbohydrates, proteins, and fats. This process takes six to eight hours, then it sends what it doesn’t use on to the large intestine.
● Eating a healthy diet with lots of fruits, vegetables, and high fiber grains; eating slowly, drinking lots of water, and getting enough sleep, all help you have a healthy small intestine.


Esophagus: A muscular tube that connects the throat to the stomach.
Pancreas: An organ that produces juices that aid in digestion and hormones including insulin.
Organ: A group of tissues that work together to do a specific job.

Questions and Answers
Question: Do tall people have longer small intestines?

Answer: The length of small intestines varies greatly, and taller people typically do have longer small intestines.

Learn more about the small intestine and the digestive system.