Different areas of the tongue carry a higher density of receptors for different tastes, even though every region can technically detect all tastes to some extent. The tip responds most strongly to sweet, the sides pick up salty and sour more easily, and the receptors most sensitive to bitter compounds sit toward the back of the tongue. This placement is not random, it triggers a gag reflex near the throat that helps the body reject potentially toxic bitter substances before they are swallowed.