Final answer:
The gastrointestinal tract is a series of organs involved in the digestion process, starting from the mouth to the anus, which breaks down food, absorbs nutrients, and expels waste.
Step-by-step explanation:
The Gastrointestinal (GI) Tract
The gastrointestinal tract, often referred to as the GI tract or digestive system, is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. The main organs that comprise the GI tract are the mouth, pharynx (throat), esophagus, stomach, small intestine, and large intestine. As part of the digestive system, the GI tract is responsible for breaking down food, absorbing nutrients, and expelling waste material.
Food begins its journey in the mouth where it is chewed and mixed with saliva to form a bolus. It then travels down the esophagus to reach the stomach. In the stomach, the food is further broken down and mixed with digestive juices, turning it into a semi-liquid substance called chyme. The chyme then passes into the small intestine, where nutrients are absorbed. Finally, the remaining waste products move into the large intestine, where they become feces before being expelled through the anus.
Accessory organs like the pancreas and liver produce digestive enzymes and bile to assist in the process of digestion, although food does not pass through these organs. The entire process from ingestion to excretion can take up to 50 hours.