The digestive system occupies part of the face where it originates, descends through the neck, crosses the thoracic, abdominal and pelvic cavity and opens to the outside, somewhat below and in front of the coccyx. In this path, the digestive system comprises six segments: the mouth, the pharynx, the esophagus, the stomach, the small intestine, the large intestine. To the above description must be added the attached glands to the digestive system: the salivary glands, the liver, the pancreas. The digestive system contributes to homeostasis by degrading food so that the body’s cells can absorb and use them. It also absorbs water, vitamins, minerals and eliminates waste. The foods we eat contain a wide variety of nutrients, which are used to form new tissues and repair damaged ones. Food is also essential for life because it constitutes the only source of chemical energy. However, most of the foods we eat are made up of molecules that are too large to be used by cells. Therefore, they must be reduced to molecules small enough to enter cells, a process known as digestion. The organs involved in the degradation of food form the digestive system.
Two groups of organs make up the digestive system:
• Gastrointestinal tract.
• Accessory digestive organs.
The gastrointestinal tract, or digestive tract, is a continuous tube that extends from the mouth to the anus. Among the accessory digestive organs are the teeth, tongue, salivary glands, liver, gallbladder and pancreas. The teeth collaborate in the physical division of food, and the tongue participates in chewing and swallowing. The other accessory digestive organs never come into direct contact with food, but instead produce and store substances that pass into the digestive tract through ducts; These secretions contribute to the chemical degradation of food.