Semidiagrammatic view of a portion of the mucous membrane of the tongue. Two fungiform papillae are shown. On some of the filiform papillae the epithelial prolongations stand erect, in one they are spread out, and in three they are folded in.
The filiform papillae (singular: papilla) are one of the four types of lingual papillae, small prominences on the surface of the tongue. The filiform papillae are thin, long "V"-shaped cones that don't contain taste buds but are the most numerous, covering most of the dorsum (upper surface). These papillae are mechanical and not involved in gustation.
They are small and arranged in lines parallel to the V-shaped row of circumvallate papillae, except at the tip of the tongue where they are aligned transversely. Projecting from their apices are numerous filamentous processes, or secondary papillae. These are of a whitish tint, owing to the thickness and density of the epithelium of which they are composed. This epithelium has undergone a peculiar modification as the cells have become cornified and elongated into dense, imbricated, brush-like processes.
They contain also a number of elastic fibers, which render them firmer and more elastic than the papillae of mucous membrane generally. The larger and longer papillae of this group are sometimes termed papillae conicae. Fungiform papillae are found dispersed throughout the filiform papillae.