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What is the Digestive System?
Several organs of your body work together to convert the food you eat into the basic nutrients your body needs to survive and thrive. The digestive system begins with the mouth and extends through the esophagus, stomach, small and large intestines, ending with the rectum and anus.
It is sometimes referred to as the gastrointestinal tract (or GT). It is considered a system because it involves several organs of the body which work together to either use nutrients or eliminate waste.
What are the Parts of the Digestive System?
The digestive system is large and complex, involving many different organs. It includes the following:
The mouth is where your tongue, jaw, lips, teeth, and several glands help you to chew and swallow your food.
The pharynx or throat is where food is transported to the esophagus.
The esophagus is a strong muscular tube which carries the food from the pharynx to the stomach. A small ring closes off the end of the esophagus and traps food in the stomach.
The stomach is a muscular sac which, in an average person, is about the size of their two fists placed side by side. It stores food so that the body has time to digest it; hydrochloric acid and digestive enzymes in the stomach continue the process.
The small intestine is a long, thin tube — coiled like a hose — about 2.54 cm in diameter and a little over three metres in length. The inside surface has ridges and folds which maximize the digestion of food and absorption of nutrients. By the time food leaves the small intestine, about 90% of all nutrients have been used.
The liver — the second largest organ in the body — is roughly triangular in shape and weighs about 1.3 kg. It has many different functions, but the main one is the production of bile, a bitter greenish-brown alkaline fluid that aids digestion and is stored in the gallbladder.
The gallbladder is a small, pear-shaped organ which stores and recycles excess bile from the small intestine so that it can be reused for the digestion of subsequent meals.
The pancreas is a large gland — about 15 cm long and shaped like a short, lumpy snake. It secretes digestive enzymes into the small intestine to complete the chemical digestion of foods.
The large intestine is a long, thick tube about 6 cm in diameter and about 1.5 metres long. It wraps around the edge of the small intestine, and it absorbs water and contains many helpful bacteria that aid in the breaking down of wastes to extract small amounts of nutrients. Feces in the large intestine exit the body through the anal canal.
What can go wrong with the Digestive System?
The digestive system is an essential part of our body; without it functioning well, it can interfere with our daily lives and make us quite miserable. There are some painful and uncomfortable problems with the system, but some treatments are available to provide relief so people can live relatively normal lives.
Here are some of the most common disorders of the digestive system:
Ulcers damage the lining of the stomach because of bacterial infections or adverse side effects of medications (most commonly aspirin, ibuprofen or naporoxen) 2. Spicy foods and stress may aggravate ulcers, but do not cause them.
Heartburn happens when stomach acid backs up into the esophagus because the lower esophageal sphincter does not close properly. It is called gastroesophageal reflux disease (or GERD) and, to be given the diagnosis, one usually suffers from the symptoms more than twice a week.
Celiac disease can cause diarrhea, bloating, abdominal pain, skin rash or a thinning of bones. In children it can cause growth failure.
Inflammatory bowel diseases include Crohn’s disease and ulcerative colitis. These conditions can be painful and debilitating, and sometimes cause malnutrition.
How might exercise help with digestive disorders?
Generally speaking, cardiovascular exercise can have a positive effect on your digestive system. Unfortunately, some runners, especially women, have found that running can cause nausea and diarrhea, acute gastris and acid relux. 3
However, there are quite a few sources that indicate that exercise — particularly cardiovascular — is beneficial to the digestive system. If you exercise regularly, some of the benefits are:
- Improves digestion and elimination 4;
- Strengthens the muscles of the abdomen and stimulates the intestinal muscles to move contents through the digestive system 5;
- Increase blood flow and oxygen circulation throughout your body;
- Reduces intestinal sluggishness by stimulating your muscles to push digestive waste through your body;
- Helps strengthen abdominal muscles.
- Can help maintain a healthy weight and may help with minor digestive problems, from bloating to constipation;
- Helps reduce stress (and stress is hard on the digestive system).
The evidence seems strong that exercise is likely to benefit the digestive system.
- Metabolism, Calorie Intake, and False Promises: Getting Through the Dieting Maze
- Canada's Food Guide: Nutrition and the Older Adult
I am a BCRPA-certified fitness instructor in Vancouver, BC. I teach four classes at the West End Community Centre in Vancouver, BC, mostly designed for the older adult. The Inevitable Disclaimer: Everything published here expresses only my opinion, based on my training and research. What you do with the information is entirely your own responsibility. I am not liable for any injury you suffer that seems to be related to anything you read here. Always consult your doctor before beginning an exercise program. For other articles, return to the table of contents.
These three dots behave exactly like a footnote. Click on them and you will get more information about the topic. ↩
According to the National Digestive Diseases Information Clearinghouse. ↩
According to James and Phyllis Balch in their book, Prescription for Nutritional Healing. ↩
Source: The Gastroenterological Society of Australia. ↩