Your digestive system is essentially one long tube that starts at your mouth and ends at your anus. Organs such as the stomach and large and small intestines digest and process the food you eat. Organs outside the digestive tract also play a part in digestion. For example, the salivary glands, tongue, pancreas and liver are all essential for digestion. The digestive process has six stages from the time you eat to the time you eliminate the waste.
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Digestion begins as soon as you put food in your mouth. Your teeth and saliva, from the salivary glands under your tongue, break down the food as you chew.
When you swallow, food enters your esophagus, which is connected to your stomach. Once the food is in your esophagus, waves of involuntary muscular contractions, called peristalsis, move the food toward your stomach.
Food enters your stomach through a muscular ring, or sphincter, that closes to keep the food in your stomach and stomach acid out of your esophagus. As you continue eating, your food's mixed with gastric acid and other digestive juices in your stomach. Then the stomach empties this mixture into the small intestine.
Small Intestine Digestion
Your food is digested more thoroughly in your small intestine, also known as the duodenum. The small intestine, as well as the liver and pancreas, produces digestive juices and enzymes that separate out the nutrients in food. Among those enzymes are lipase and amylase from the pancreas. Muscular contractions keep the food moving along toward the large intestine.
The digested food continues its journey into the large intestine. The nutrients -- fats, carbohydrates and proteins, for example -- have been broken down and are ready to be absorbed through the intestinal walls into your bloodstream for transport throughout your body.
Waste products from digestion are not absorbed through the intestinal walls but continue moving through your digestive tract into the colon. Waste products include dietary fiber. Waste products leave your body via bowel movements.