Human Digestive System Basics

Human Digestive System Diagram

The human digestive system consists mainly of a complex system of tubes and hollow organs, known as the digestive or gastrointestinal tract. This tubular passageway reaches all the way from your mouth to your anus, and as a mature adult, these coiled tubes measure an astounding length of approximately twenty-two feet (6.7 metres)!

Organs that make up your digestive tract are the mouth, esophagus, stomach, small intestine (small bowel), large intestine (large bowel/colon) rectum, and anus.

You also have a number of additional digestive organs, which whilst not part of your main digestive tract are still connected to the system. These accessory organs include your salivary glands, gallbladder, pancreas and the liver. You can see the main component parts of the digestive system in our labeled digestive system diagram to the left. You can also click here to learn more about the individual organs of the digestive system.

What Does The Human Digestive System Do?

The human digestive system is a wondrous multi-function machine, able to undertake its numerous task constantly and simultaneously. It serves as:
  • A giant food processor, which breaks down the food and drink we consume into nutrients that can be absorbed into our blood.

  • An energy provider, providing our cells with the nutrients they require, which in turn gives us energy. This energy provides us with the strength for our physical activities such as walking, working, playing sport and talking as well as for the normal functioning, building, restoring, and repairing body tissues, organs and systems.

  • A top rate waste disposal system collecting, transporting, processing and disposing of “trash” products that our bodies do not require.

What’s more our digestive systems (notably the colon or large bowel/intestine)1 are home to trillions of microorganisms.

The Human Digestive System, Health and Disease

The human digestive system is key to good health. Good digestion results in good health and an important prerequisite for good digestion is the maintenance of a well-balanced digestive flora. Conversely poor digestion results in poor health: the most obvious manifestation of long-term inadequate digestion being digestive disease.

Each year millions of Americans suffer from digestive illness with these problems affecting men, women and children alike. Some will experience Irritable Bowel Syndrome (IBS), whilst others will develop inflammatory bowel diseases such as Crohn’s Disease or types of colitis.

Likewise many others will have digestive problems including pouchitis, intestinal Candida overgrowth, food sensitivity (also known as food intolerance) Clostridium Difficile (C. Diff), antibiotic associated diarrhea, Helicobacter Pylori infection and diverticulitis among others. For some these problems will be acute, for others chronic.

Although the science regarding digestive flora is still in its infancy, it is generally accepted that gut flora plays a role in digestive diseases. As a result a whole host of research has been conducted on the therapeutic use of probiotics for treating such diseases.

Current evidence suggests that probiotics can help restore normal digestion2, rendering them very helpful in the treatment of digestive complaints and diseases. Indeed their use as a treatment has been proven for conditions including antibiotic-induced diarrhea and types of infectious diarrhea3.

Additionally preliminary results also suggest that probiotics may be helpful in pouchitis 4, irritable bowel syndrome (IBS)5, and food sensitivity (also known as food intolerance)6 among other treatments.

Have a look at our pages on the following digestive diseases to learn more on the use of probiotics for specific digestive problems:


1.The stomach and the small intestine are thought to contain only a few species of bacteria.

2.Marteau PR, et al.,Protection from Gastrointestinal Diseases with the Use of Probiotics,American Journal of Clinical Nutrition73(2, Suppl 1): 430S-436S, 2001.

3.Anuradha S, et al, Probiotics in Health and Diseases, Journal of the Indian Academy of Clinical Medicine, Vol 6, No 1

4.Marteau PR, et al., Protection from Gastrointestinal Diseases with the Use of Probiotics, American Journal of Clinical Nutrition 73(2, Suppl 1): 430S-436S, 2001.

5.Hunter J O, Irritable Bowel Solutions, Vermillion, 2007

6.Hunter J O et al, The Management of Multiple Food Intolerances, Foods Matter, December 2009

Return from Probiotics for Human Digestive System Diseases to Probiotics Help Home Page Home Page

Share this page:
Enjoy this page? Please share it with others. Here's how..

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.