Swallowing

When food or drink passes on to the posterior part of the tongue, the muscles supplied by the nucleus ambiguus through the vagus (X) and glossopharyngeal (IX) nerves propel it backwards and downwards into the hypopharynx, thence through the cricopharyngeal sphincter to the oesophagus. The nasopharynx is closed by the palatal muscles (X, Vc), and the Eustachian tube opens (X). The laryngeal orifice is reduced in size largely as a result of elevation of the entire laryngeal skeleton by all the muscles attaching to it from above, and the cricopharyngeal sphincter opens (X). The tongue muscles (XII) also have an important role in these actions. Most of the muscles of the pharynx are supplied in one way or another by the nucleus ambiguus through the vagus (it is unnecessary to bother with individual pharyngeal muscles).

Sensation from this region is conveyed through the pharyngeal plexus, the glossopharyngeal (posterior tongue, oropharynx) and vagus (hypopharynx) nerves, to the nucleus of the solitary tract.

Speaking

Noise production: phonation

The vocal cords create the narrow slit through which air is directed to make a sound, much as in an oboe, recorder or organ pipe. Muscles which move the cords are supplied by the recurrent laryngeal nerve (X).

Making the noise intelligible: articulation

The pharyngeal muscles (X), the tongue (XII), the muscles of facial expression (VII), mandibular movements (Vc) and the palate (X, V) all modify the crude noise produced by the larynx to create speech.