Oral+Preparation


 * Oral Preparation **

As the name suggests, this stage is when the food is deformed and in the mouth, and prepared into a bolus ready to be swallowed. The oral preparatory stage is characterised by the production of saliva, the deformation of food, and the containment of the bolus. For obvious reasons, not all of the following information will be relevant to the swallowing of liquids due to the difference in consistency. The following diagram is a representation of the bolus (the black area) during oral preparation.



__ Production of Saliva __

The presence of food in the mouth will stimulate various receptors such as taste, temperature and pressure receptors. Saliva is produced from salivary glands following the triggering of taste receptors, as well as the mechanical motion of chewing. The actions that encourage saliva production are the movement of the jaw, tongue and hyoid bone (Groher & Crary, 2010).

Saliva serves many functions in deglutition. It breaks down carbohydrates in food, it facilitates the taste and formation of the bolus, promotes oral hygiene, and even regulates stomach acidity (Groher & Crary, 2010).

__ Deformation of food __

The majority of the deformation of food is achieved through mastication. Mastication involved repetitive, crushing movements of the mandible; which breaks down the structure of the food, and reduces each portion in size (Groher & Crary, 2003). The tongue has two roles in the deformation of food. Firstly, it pushes laterally, which places and keeps the food on the molar table during mastication. Secondly, further deformation occurs by through the tongue pressing against the hard palate (Groher & Crary, 2010).

__ Containment __

Containment of liquid is performed anteriorly by creating a lip seal. Posteriorly, it is achieved through contact of the tongue and the velum. With solid boluses, containment is performed in the same manner. However, due to consistency of solid food boluses, it is possible for the oral preparatory stage to occur without lip closure (chewing with your mouth open). Posterior containment is also not always required, as material is even allowed to collect in the vallecula during this stage of deglutition (Groher & Crary, 2010).


 * References **

Groher, M., & Crary, M. (2010). Dysphagia: Clinical management in adults and children. Maryland Heights, MO: Mosby Elsevier.