In humans, the surface of the top of the tongue is covered in many tiny projections called papillae that contain the taste buds. Food chemically stimulates the nerves of the tongue resulting in the sense of taste. Each section of the tongue has receptors for a specific taste sensation. The base of the tongue senses bitterness, the sides sense sourness, and the tip recognizes both sweetness and saltiness. The taste buds are responsible for sending the taste sensations, along with information regarding the consistency and temperature of food, to the nervous system.