Final answer:
The cheeks differ from adjacent structures like the lips in terms of their anatomical structure, with cheeks lined internally by a non-keratinized mucous membrane and containing buccinator muscles, while the lips have a mucous membrane and the orbicularis oris muscle with significant cerebral cortex representation.
Step-by-step explanation:
The main difference between cheeks and the parts right near them, such as the lips, is in their anatomical structure and function. Cheeks constitute the oral cavity's sidewalls and have an outer covering of skin, while their inner lining is a mucous membrane made up of non-keratinized, stratified squamous epithelium. Within this structure, connective tissue and the buccinator muscles play a crucial role. In contrast, the lips, which border the cheeks, have an outer layer of skin that transitions to a mucous membrane inside the mouth. They contain the orbicularis oris muscle and have a significant representation on the cerebral cortex, highlighting their importance in expressions such as kissing and speaking. The distinction is also apparent when considering the oral vestibule, which is the pocket-like part bordered externally by the cheeks and lips and internally by gums and teeth.