False-colour scanning electron micrograph (SEM) of a filiform papilla emerging from the tongue's surface. It is partly covered by green coloured bacteria which may derive from a mouth infection. Filiform papillae, also known as conical papillae, are covered by epithelial cells apart from their white tips which are formed by the fibrous protein keratin in order to increase the papillae's strength. Filiform papillae have mechanical and tactile functions. They form a rough surface which helps mastication. Each papilla contains nerve endings which transmit tactile information to the brain. Magnification: x1100 at 6x7cm size.