The tongue is usually flat and moderately extensible. It consists of a network of bundles of striated muscle fibers, fibrous tissue, fat and lymphoid masses, mucus-producing glands, and a covering of mucous membrane.
It is an extremely mobile muscle that enables you to taste food, move it around as you chew, push it back into your pharynx (throat) when swallowing, and is an invaluable aid in speech. It is derived mostly from an outgrowth (tuberculum) in the floor of the pharynx. The tuberculum grows forward and is joined by other tissues from the region, forming this complex muscular organ of many uses.