The digestive system functions to break down food that goes inside the body. It converts the food into energy and nutrients or waste which is eliminated by the body. The organs present in this system are where the food passes through which starts from the mouth up to the anus.

The nonkeratinized stratified squamous epithelium in the mouth makes up the oral mucosa. This tissue has many layers of flat cells. It is found in the thick lining of the oral cavity. This tissue serves as protection and covering for the mouth since it is prone to wear and tear. It functions to provide support for the stress and friction that the mouth goes through during mastication or chewing.

The areolar tissue in the stomach keeps the organ in its place. It is weblike in appearance due to the collagen fibers present. It contains a gelatinous extracellular matrix where fibroblasts are also seen. This tissue fills the spaces between muscle fibers and is a component of the mucus membranes of the digestive system. It is also used as attachment for the epithelial tissue which makes the areolar tissue a binding site for the stomach lining and the muscular coat.

The simple columnar epithelium in the rectum functions mainly for protection. It serves as an impermeable barrier against bacteria and other foreign substances that may have been ingested. This tissue also lines most of the digestive tract and plays a role in the absorption and secretion of substances.