This chapter describes how the mouth operates, placing this in the context of a general physiological model. The chapter draws extensively on data from humans because the need for cooperation in many chewing experiments exceeds that which can be obtained from trained animals.
The literature on mastication and swallowing is vast and it is impossible to cite more than a small fraction of the papers that comprise it. Emphasis has been placed here on those papers that describe facts relevant to physiological modelling of the process, however primitive such models might be at this point. Central to unravelling what happens to food particles in the mammalian mouth have been cine- and video-fluoroscopic studies. These date back to Ardran et al. (1958) on the rabbit, through Crompton & Hiiemae (1970) on the American opossum, up to the present. These X-ray movies have permitted views of the intra-oral processing of food otherwise obscured by the cheeks. Excellent reviews are available (e.g. Hiiemae & Crompton, 1985; Orchardson & Cadden, 1998; Thexton & Crompton, 1998) as well as studies on particular species. It has required the combination of a wide range of experiments and detailed observation (e.g. Weijs & Dantuma (1981) on the rabbit) to establish the major features of oral processing. However, I have yet to see some synthesis that attempts to weld all this information on mastication and swallowing together.