Pharyngeal reflex

The pharyngeal reflex or gag reflex (also known as a laryngeal spasm) is a reflex contraction of the back of the throat, evoked by touching the roof of the mouth, the back of the tongue, the area around the tonsils, the uvula, and the back of the throat. It, along with other aero digestive reflexes such as reflexive pharyngeal swallowing, prevents something from entering the throat except as part of normal swallowing and helps prevent choking.