Oral Preparatory Phase:
Voluntary phase. Liquid and food is manipulated to form a bolus. During this phase, bolus is located between the tongue and hard palate, and soft palate is lowered to prevent bolus escaping into the pharynx. The air way is open.
Voluntary phase. Soft palate is elevated and food is moved towards the pharynx by peristaltic movement. There is simultaneous closure of the naso-pharynx.
Voluntary and involuntary phase. Bolus is transported through the posterior pharynx. Larynx is closed to protect the airway and upper oesophageal sphincter opens.
Involuntary phase. Follows each pharyngeal phase. Bolus is transported to stomach by peristaltic movement.