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. The sublingual vein drains into the lingual vein, which then flows into the internal jugular system. The sublingual glands receive their parasympathetic input via the chorda tympani nerve, which is a branch of the facial nerve via the submandibular ganglion. The nerve functions in a secretomotor capacity. The chorda tympani branches from the motor branch of the facial nerve in the middle ear cavity, which then exits the middle ear through the petrotympanic fissure. The chorda tympani nerve then travels with the lingual nerve to synapse at the submandibular ganglion. The postganglionic fibers reach the sublingual gland, and release acetylcholine and substance P. Acetylcholine, the primary neurotransmitter and the muscarinic receptors work to increase salivation.