Taste and smell are linked both in biology -- their respective sensory organs are located close together and share a common airspace -- and in the mind. Both rely on touch-specific nerve endings: nerves that require the sensed chemical to touch them for activation. Taste is taken care of by thousands of "taste buds" on the tongue and in the mouth, while smell is only activated in a small, isolated patch of nerves in the nasal passage. While eating, air from the mouth travels through the nasal passages and sinuses, causing the "smell of the taste" to activate the sense of smell and so work with taste for a sensory experience. Many people find that their sense of taste is diminished when they hold their nose, and people without a sense of smell often cannot identify foods as easily. Certain smells are also associated with taste in the mind, and so eating a certain food, even without deliberately smelling it, evokes a taste response based on the memory of the food's smell. People also find that holding the nose helps with eating or drinking things that taste bad; the sense of taste is dulled without the sense of smell backing it up.