The buccal mucosa is a specific area of the oral mucosa — a mucous membrane covering the mouth area. The buccal mucosa area of this membrane extends around the inside of the cheek and lower mouth area, the bottom of the tongue, out to the lips and to the back of the throat. This region is well known to dentists and oral surgeons, since it surrounds the tooth structures in the lower jaw and contains muscles used during chewing. It also contains a fat pad between the muscles — called the buccal fat pad — as well as nerves, blood vessels, and lymph glands.
The buccal mucosal membrane secretes moisturizing and lubricating fluids for the mouth and upper throat. These fluids are necessary to prevent drying effects, since this mucosa is part of the membrane system that lines the entire gastrointestinal tract, and this is open to exterior surfaces at both ends. A similar type of membrane also lines the exterior entrances to the respiratory system at the nose and throat areas.
The epithelial tissue — the tissue covering body surfaces — of the buccal mucosa is characterized as “squamous.” This means that this tissue consists of cells that are flattened — similar to the mesh in a fishnet — but since squamous tissue has several layers, a more accurate description would be of several overlaid fishnets. Because the cells are flattened, however, they can more easily transfer substances such as saliva throughout the mouth due to their reduced vertical dimensions, and this aids the digestive process.
The parotid gland, a large gland that produces saliva for the mouth as an aid in digestion, flows into an area of the buccal mucosa near the second upper molar, known as the buccal cavity or the inner surface of the buccal mucosa. The region around the molars is also known as the soft palate, an area of soft tissue at the upper back of the mouth that closes off air passages when swallowing or speaking. While the soft palate is part of the buccal mucosa, however, it does not continue on to extend up to the roof of the mouth, which is an area known as the hard palate.
The epithelial tissue of the buccal mucosa is non-keratinised, which means that these cells have a nucleus, or central generating core, as well as cytoplasm, which consists of all living structures in a cell apart from the nucleus. This is in contrast to squamous epithelial cells that cover drier areas of the body, such as the skin, which are keratinized and have lost cell regeneration capabilities. Both types of epithelial tissue, however, are highly subject to cancers, since epithelial tissue is known as having a high cancer rate.
The squamous epithelial tissue of the buccal mucosa area is particularly subject to cancer, and over 90% of oral cancers have been associated with squamous cell carcinomas of the mouth and lip areas. Many of these cancers have been associated with imbibed or inhaled substances, in addition to physiological causes. Additionally, according to the Centers for Disease Control and Prevention (CDC) of the U.S. Government, cancers in this area have also been associated with human papillomavirus, or HPV infections, with up to 35% of oral cancers now being caused by this virus.