The |mouth| is a versatile area of the human anatomy, responsible for articulation in speech, and tasting, chewing, and swallowing food. The |mouth| cavity is located just below the |nasal cavity| and is formed by the |palatine bones| and the |palatine processes| of the |maxilla| on top and by the |mandible| on bottom. At the opening of the mouth cavity are the |lips| - muscular structures which are covered with thin, membranous skin. The |lips| occlude the |mouth| opening during chewing to keep food and liquid within, help manipulate food during chewing, facilitate articulation in speech, and even give a friendly kiss. Within the |mouth| cavity, the |teeth| extend down from their maxillary sockets and up from their mandibular sockets to form the dental arcade. The muscles and skin of the cheeks cover the outer sides of the |mouth| cavity, while the muscular structures of the |tongue| and sublingual mucosal lining and muscles.
When food is brought into the |mouth|, the |lips| close (except in some unruly children) while the salivary |glands| produce saliva. The saliva lubricates the |mouth| and moistens the food. The inner surface of the |lips|, the |tongue|, and the cheeks manipulate the food so that it is brought between the |teeth| as the |teeth| clamp down on the food. In a combined action of these motions, with a semi-circular, grinding motion of the |teeth|, the food is chewed into a paste with the saliva. ~Enzymes~ within the saliva begin to break down the food and the |tongue| moves a portion of this food paste to the back of the |mouth| cavity by pressing it up and back along the |hard palate|. The soft palate, meanwhile, raises to seal off the |nasal cavity|. The ball of food paste, called a ~bolus~, is passed into the |pharynx|. The |epiglottis| lowers to cover the airway so that the food does not enter the |larynx|. From the |pharynx|, wave-like |contractions|, called peristalytic waves, push the ~bolus~ down into and through the |esophagus| and into the |stomach|, where it is further digested.