The gastrointestinal or digestive tract (also known at the GI tract or gut) is the system of organs which remove and process nutrients (vitamins, minerals, carbohydrates, fats, proteins and water) from foods and helps pass waste material out of the body.
The gastrointestinal tract is made up of the oesophagus, stomach and the small and large intestines.
The oesophagus is the hollow muscular tube that moves food and liquid from the throat to the stomach. The wall of the oesophagus is made up of several layers of tissue, including mucous embrane,muscle and connective tissue.
The stomach is a J-shaped organ in the upper abdomen. The stomach helps in the digestion of food by mixing it with digestive juices and churning it into a thin liquid. After leaving the stomach, partly digested food passes into the small intestine and then into the large intestine.
The small intestine mainly absorbs nutrients from broken down food.The colon (the first 1.8 metres of the large intestine) mainly absorbs water and the rectum and anal canal (the last 15 centimetres of the large intestine) stores waste material (faeces) until they are passed from the body through the anus.
The anal canal ends at the anus, the opening of the large intestine to the outside of the body. The colon and rectum together are known as the large bowel.
Anatomy of the lower digestive system.