The oral cavity is not simply the entrance to the gastrointestinal tract (GIT), but consists of a complex system of tissues and organs with a variety of functions which together are involved in selecting food that is suitable for intake and processing the food into a form that is suitable for passage into the rest of the GIT. Another major function of the oral cavity is speech production. With regard to its feeding function, the oral cavity contains several sensory systems which are involved in perceiving the taste, smell, touch, and temperature of the food. This sensory information is analysed in the central nervous system and used to determine the acceptability of the food. If it is regarded as acceptable, then saliva is secreted, chewing is initiated, and eventually swallowing takes place.

Anatomy and physiology of the oral cavity

The oral cavity is formed from the cheeks, the hard and soft palates, and the tongue (Figure 8.1). It contains accessory digestive structures, the teeth, and is connected to the pharynx by an opening known as the fauces. The total surface area of the oral cavity is approximately 200 cm2. The surfaces of the teeth comprise 20% of this, with the remainder being attributable to the oral mucosa. The oral mucosa, like other mucosal surfaces, consists of two layers – an epithelium and an underlying layer of connective tissue, the lamina propria.