The GI tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. The hollow organs that make up the GI tract are the mouth, esophagus, stomach, small intestine, large intestine, and anus. The liver, pancreas, and gallbladder are the solid organs of the digestive system.

What does the digestive system do?

It breaks down and absorbs nutrients from the food and liquids you consume. Your digestive system also takes care of food waste — the stuff that’s left over after you digest food. Digestion starts even before you take that first bite of food. When you see and smell food, your salivary glands get to work. They release saliva so you have some spit in your mouth to moisten food when you start chewing.

stomach is a muscular organ that digests food. It is part of your gastrointestinal (GI) tract. When your stomach receives food, it contracts and produces acids and enzymes that break down food. When your stomach has broken down food, it passes it to your small intestine. The lining of the stomach consists of several layers: the mucous membrane tissue covering the inside of the stomach, and the connective tissue with blood vessels, nerves, and muscle tissue. The muscle layer is made up of three sub-layers that each pull the stomach in different directions. They move the contents of the stomach around so vigorously that solid parts of the food are crushed, churned and mixed into a food pulp.