All taste buds are able to detect each of the four basic taste sensations. However, each taste bud is usually most sensitive to one type of taste stimuli. The stimulus type to which each taste bud responds most strongly is related to its position on the tongue. Sweet receptors are concentrated at the tip of the tongue, while sour receptors are more common at the sides of the tongue. Salt receptors occur most frequently at the tip and front edges of the tongue. Bitter receptors are most numerous at the back of the tongue.