The digestive system includes all the organs involved in digestion, or the breaking down of food into nutrients that the body uses for energy to fuel many processes, including growth and cell repair. It includes the alimentary tract, the liver, the pancreas, and the gallbladder.
The alimentary tract, also called the digestive tract, is a series of hollow organs through which food passes. These organs include the mouth, the esophagus, the stomach, the small intestine, the large intestine, and the anus. The large intestine is also known as the colon and includes the rectum.
As food moves through the alimentary tract, it mixes with digestive juices that break the food down into smaller molecules and nutrients. These nutrients include carbohydrates, protein, fats, and vitamins.
The body absorbs the nutrients through the walls of the small intestine into the bloodstream, which delivers them to the rest of the body. Waste products of digestion pass through the large intestine and out of the body as solid matter called feces or stool.
Along with digestive juices, bacteria in the digestive tract, sometimes called gut flora or microbiome, help with digestion. Nerves, hormones, and blood also play roles in this digestive process.