The medical term for the act of swallowing is deglutition. Swallowing is actually a complex process whereby broken down food in the mouth is transferred from the mouth through the pharnyx and esophagus and ultimately into the stomach. Swallowing can be broken down into three different phases: oral, pharyngeal, and esophageal.
The oral phase involves the breaking down of food using teeth and salivary enzymes. The tongue then pushes the food into the pharyngeal phase. For the food to pass through the throat effectively, the nasopharynx and larynx (voice box) must be closed off by various muscles to prevent food from contaminating these areas. Also, the epiglottis closes off the trachea so no food enters the windpipe. A large number of muscles are involved in this phase. The final phase is the esophageal phase. The food passes through the upper sphincter and various muscles push it down the esophagus, through the lower sphincter, and into the stomach. It should be noted that the final two phases are involuntary and controlled by the brain.