Parts of the Digestive System

The digestive system is the group of organs that break down food in order to absorb its nutrients. The nutrients in food are used by the body as fuel to keep all the body systems working.

The leftover parts of food that cannot be broken down, digested, or absorbed are excreted as bowel movements (stool).

Illustration of the digestive system

Organs of the Digestive System

Several organs make up the digestive system. Every organ has a role in breaking down food and managing the waste material.

The digestive organs, in the order in which food travels through them, are:

Mouth: Digestion starts at the very beginning, with food being chewed in the mouth.

Food is broken down into smaller pieces and the saliva in the mouth begins digesting it. An enzyme in saliva called amylase breaks down certain starches down into the smaller sugars, maltose, and dextrin.

Esophagus: The esophagus is a tube inside the throat, behind the windpipe.

After food is chewed and swallowed, it travels down through the esophagus to the stomach. The muscles in the esophagus contract to move food along, which is called peristalsis.

Stomach: After the food is deposited in the stomach, the digestive process continues.

The food is mixed with the acids and enzymes that are secreted from the stomach wall. After the food is thoroughly broken down, it's moved along into the small intestine.

Small Intestine: The small intestine is a long tube where most of the vitamins and nutrients are absorbed from food into the bloodstream.

More enzymes are added into the small intestine as the food moves through to help facilitate the process. The small intestine is composed of three parts:

  • Duodenum
  • Jejunum
  • Ileum

Large Intestine: After moving through the small intestine, the food is now partially digested and mostly in a liquid form as it passes through a sphincter called the ileocecal valve and enters the large intestine.

The large intestine is where much of the water is absorbed from the waste material. By the time the stool reaches the end of the large intestine, it's in a more solid form. The sections of the large intestine are called:

  • Cecum
  • Ascending colon
  • Transverse colon
  • Descending colon
  • Sigmoid colon

Rectum: At the end of the large intestine is the rectum, a reservoir that holds stool until it can be passed out of the body.

When the rectum becomes full of stool, it gives off a signal to the brain that it's time to go to the bathroom.

Anus: The anus has two sphincters that serve to hold stool inside the body until it is time to pass it. When you consciously relax your external sphincter, the stool can then leave the body.

The digestive tract forms one long tube through the body, all the way from the mouth to the anus (with some sphincters between organs to keep things moving in the right direction).

Removing Parts of the Digestive System

When the digestive system is affected by certain diseases, surgery may be used as a treatment. This is true in particular cases of cancer and in severe cases of inflammatory bowel disease (IBD).

Some parts of the digestive tract can be removed in part or in full:

  • The large intestine can be removed partially or fully in an ileostomy or colostomy. or J-pouch surgery. Most people live full and productive lives after these surgeries.
  • The rectum and the anus can be removed, which is also called ileostomy or colostomy.
  • Parts of the small intestine can be removed, but since this is where most nutrients are absorbed, an effort is made to keep it as intact as possible.
  • Part of the stomach can be surgically removed, and people can live well after this surgery as well.
2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. National Library of Medicine. MedlinePlus. Large bowel resection.

  2. U.S. National Library of Medicine. MedlinePlus. Small bowel resection.

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.