The glossopharyngeal nerve consists of five components with distinct functions:
Branchial motor
(special visceral efferent)
Supplies the stylopharyngeus muscle.
Visceral motor
(general visceral efferent)
Parasympathetic innervation of the smooth muscle and glands of the pharynx, larynx, and viscera of the thorax and abdomen.
Visceral sensory
(general visceral afferent)
Carries visceral sensory information from the carotid sinus and body.
General sensory
(general somatic afferent)
Provides general sensory information from the skin of the external ear, internal surface of the tympanic membrane, upper pharynx, and the posterior one-third of the tongue.
Special sensory
(special afferent)
Provides taste sensation from the posterior one-third of the tongue.