OPTION 1

DEGLUTITION REFLEX
Though the beginning of swallowing is a voluntary act, later it becomes involuntary and is carried out by a reflex action called deglutition reflex. It occurs during the pharyngeal and esophageal stages.
Afferent Fibers:
֍ Afferent impulses from the oropharyngeal receptors pass via the glossopharyngeal nerve fibers to the deglutition center.
Center
֍ The deglutition center is at the floor of the fourth ventricle in medulla oblongata of brain.
Efferent Fibers:
֍ The impulses from deglutition center travel through glossopharyngeal and vagus nerves (parasympathetic motor fibers) and reach soft palate, pharynx and esophagus.
֍ The glossopharyngeal nerve is concerned with pharyngeal stage of swallowing. The vagus nerve is concerned with esophageal stage.