The tongue is a muscular organ found in most vertebrates made up of moist, pink tissue known as mucosa. The top of the tongue is covered with bumps called papillae, and each has thousands of taste buds that are connected to the brain through the nervous system. The underside of the tongue has a smooth texture and is anchored to the mouth by a web of mucosa. The primary functions of the tongue are taste, speech, digestion and cleaning.
The primary parts of the tongue are the root, body and apex. The root is the section of the tongue closest to the achoring point in the mouth. The body consists of the large center portion of the tongue. The apex is the area near the tip of the tongue, and it serves as the most mobile portion of the tongue. There are several folds on the tongue that divide it into different regions.
In humans, the tongue comprises four intrinsic muscles that are not attached to any bone, as well as four extrinsic muscles that are attached to bone. The intrinsic muscles are used to retract or extend the tongue, while the extrinsic muscles are used to move the tongue.
There are several types of papillae or taste buds found on the top surface of the tongue. Vallate papillae are large and flat papillae arranged in a V-shaped formation near the rear-center portion of the tongue. Foliate papillae are found on the sides of the tongue. Filiform papillae are sensitive to touch and are usually long and conical. Fungiform papillae are found densely packed near the tip of the tongue.