Where Does the Digestive Tract Start and End?

The human digestive tract starts at the mouth and ends at the rectum. In between, food and drink pass through the esophagus, stomach, small intestine and colon. In addition, other organs aid digestion, including the pancreas, liver and gallbladder.

Digestion begins in the mouth, where the teeth break the food down and enzymes in the saliva start to break it down. From there, it moves through the esophagus in a partially digested format. When it reaches a sphincter that separates the esophagus and the stomach, it gradually passes through.

Once in the stomach, further digestive enzymes and stomach acids begin working on the food to break it down further. Over a few hours, the stomach turns it into chyme, which is a liquid-like substance. The food then sits in the stomach for a short while before moving into the small intestine. In the duodenum portion, it is broken down further, then the jejunum and ileum extract nutrients and pass them through to the bloodstream. During this time, the pancreas, liver and gallbladder produce enzymes that assist with breaking the nutrients down. After this, the food passes through to the small intestine, which extracts electrolytes and fluids from it. Finally, the remaining matter, which is feces, passes through the rectum.