Sublingual (abbreviated SL), from the Latin for "under the tongue", refers to the pharmacological route of administration by which substances diffuse into the blood through tissues under the tongue which is predominantly a mucous gland that produces a thick mucinous fluid and lubricates the oral cavity which allows for swallowing, initiating digestion, buffering pH, and dental hygiene.The sublingual glands receive their primary blood supply from the sublingual and submental arteries, which are branches of the lingual artery and facial artery, respectively. These arteries are both branches of the external carotid artery. [Source: Wikipedia 
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