The gastrointestinal tract (GI tract) is a system, but not in the same way we might talk about a "system" like the nervous system or the circulatory system.

Here's why:

* It's a part of a larger system: The GI tract is a subsystem of the digestive system. The digestive system as a whole includes the GI tract, along with accessory organs like the liver, pancreas, and gallbladder.

* It's a complex organ: The GI tract is technically a single, long, continuous organ made up of several parts (mouth, esophagus, stomach, small intestine, large intestine).

* It works as a unit: Each part of the GI tract has a specific function, and they all work together to break down food, absorb nutrients, and eliminate waste.

So, while it's not a standalone "system" like the nervous system, the GI tract is a complex, integrated part of the larger digestive system.