Which of the following is NOT considered an accessory organ of the digestive tract?

The esophagus is not considered an accessory organ of the digestive tract because it serves as a primary component in the digestive system responsible for transporting food from the mouth to the stomach. Accessory organs, on the other hand, are those that aid in digestion but are not part of the digestive tract itself. They include organs such as the liver, gallbladder, and pancreas, which produce or store substances that assist in the digestive process. For instance, the liver produces bile, the gallbladder stores bile, and the pancreas produces digestive enzymes that help break down food in the small intestine. This distinction between primary digestive organs and accessory organs is crucial in understanding the anatomy and function of the digestive system.