What are the Functions of the Digestive System?

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  • Written By: Erin J. Hill
  • Edited By: Bronwyn Harris
  • Last Modified Date: 15 March 2020
  • Copyright Protected:
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The functions of the digestive system are varied, but they mostly involve the breaking down and absorption of food and nutrients. The stomach, small intestine, and large intestine, combined with organs like the liver and pancreas, work together to break down food materials and absorb the nutrients they contain so that they can be used by the body. Many areas of digestion also affect the body’s immune system and detoxification system.

Breaking down food so that it can be used is the first of many functions of the digestive system. This begins in the mouth where saliva helps dissolve and liquefy food and continues in the stomach where digestive enzymes break foods down further. Once it leaves the stomach, food goes into the small intestine, which is a long tubular organ that absorbs the bulk of food’s nutrients.

Food is broken down even more in the small intestine by using bile from the pancreas and enzymes produced by the liver, as well as digestive mucus. Nutrients are absorbed into the tissues of the intestines and the remaining waste materials move downward into the large intestine, or colon. It is generally in liquid form by this time, but the colon reabsorbs moisture from the waste to prevent dehydration. Occasionally, the water is not absorbed, and this is what causes diarrhea.


There are other functions of the digestive system aside from providing nutrients for the rest of the body. The liver, which secretes important enzymes and bile for breaking down food, also works to detoxify the body by filtering toxins from food, drink, and other consumed substances. Both the kidneys and gallbladder help with this process, but the liver does the bulk of the work.

The pancreas also performs various important functions of the digestive system, including secreting insulin into the bloodstream to metabolize glucose so that it can be used as fuel by cells. If this isn’t done properly, serious health complications can result. An improper production or implementation of insulin is what causes diabetes.

Additionally, good bacteria which live in the large intestine help to thwart pathogens or harmful bacteria. This helps the immune system to keep the body free of disease by reducing the numbers of harmful bacteria that white blood cells have to fight off. Imbalanced dangerous bacteria is one of the main causes of digestive upset. Taking a daily probiotic supplement may help to maintain balance.



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