The digestive system is a group of organs that work together to convert food into basic energy and basic nutrients to feed the entire body. The food that you swallow goes through a long tube inside your body known as the alimentary canal or gastrointestinal tract (GI tract). The GI tract made up of:
The journey of food through the digestive system begins in the mouth, another way to say oral cavity. Within the mouth, there are many accessory organs that aid in the digestion of food-the tongue, teeth, and salivary glands. Teeth break down food into smaller pieces, which are then moistened by saliva before the tongue and other muscles push food into the pharynx. The pharynx, which is another way of saying throat, is a funnel-shaped tube connected to the posterior end of the mouth. It is responsible for the passing of masses of chewed food from the mouth to the esophagus. The pharynx also plays an important role in the respiratory system (More info About the Respiratory System). The esophagus is a muscular tube connecting the pharynx to the stomach that is part of the upper GI tract. It carries swallowed masses of chewed food along its legnth. At the inferior end of the esophagus is a muscular ring called the lower esophageal sphincter/cardiac sphincter. The purpose of the sphincter is to prevent backflow from the stomach acids going back into the esophagus. The stomach is a muscular sac that is located on the left side of the abdominal cavity, just inferior to the diaphragm. The stomach hold the hydrolytic acids (uses hydrolysis to break down food) and digestive enxymes that continue the digestion of food that began in the mouth. After going through the stomach, the food goes to the small intestine, which is part of the lower GI tract. There are many folds within the small intestine to increase the surface area, which maximizes the digestion of foods and absorption of nutrients. The liver is a roughly triangular accessory organ of the digestive system located to the right of the stomach, just inferior to the diaphragm, and thhe main function of the liver in digestion is to produce bile and its secretion into the small intestine. The gallbladder is a pear-shaped organ located just posterior to the liver. The gallbladder is used to store and recycle excess bile from the small intestine so that it can be reused for the digestion of subsequent meals. The large intestine is a large, thick tube that absorbs water and contains many symbiotic bacteria that aid in the breaking down of wastes to extract some small amounts of nutrients. The feces from the large intestines exit the body through the anal canal.
Here are all of the main organ systems of the human body and some info about them: