In animal organisms, the digestive system is the organ system that transforms food into simple substances in a process called digestion. After digestion, the body can absorb these substances and use them to obtain energy and maintain the body.

In humans, it consists of the following organs:

The mouth: contains the teeth, which bite and chew food. The tongue mixes food with saliva and pushes it down the throat.
The esophagus: serves as a passageway for food between the throat and the stomach. Once it has reached the esophagus, the food automatically passes into the stomach.
The stomach: grinds and mixes food with acidic and digestive substances called enzymes.
The pancreas: produces the enzymes that facilitate the transformation of food.
The liver: produces and releases digestive substances in the small intestine. It also stores sugars and releases them into the blood according to the body’s needs.
The small intestine: it is a long and thin tube, more than 5 m in length. In it most of the process of digestion and absorption of food takes place. The released enzymes degrade the food. The small intestine empties into the large intestine.
The large intestine: it is a wide tube 1.5 m in length, located in the abdomen. Through the large intestine it absorbs water and useful chemicals. The excess material is driven and excreted through the anus.