<P> Hearing or audition (adjectival form: auditory) is the sense of sound perception . Hearing is all about vibration . Mechanoreceptors turn motion into electrical nerve pulses, which are located in the inner ear . Since sound is vibration, propagating through a medium such as air, the detection of these vibrations, that is the sense of the hearing, is a mechanical sense because these vibrations are mechanically conducted from the eardrum through a series of tiny bones to hair - like fibers in the inner ear, which detect mechanical motion of the fibers within a range of about 20 to 20,000 hertz, with substantial variation between individuals . Hearing at high frequencies declines with an increase in age . Inability to hear is called deafness or hearing impairment . Sound can also be detected as vibrations conducted through the body by tactition . Lower frequencies that can be heard are detected this way . Some deaf people are able to determine direction and location of vibrations picked up through the feet . </P> <P> Taste or gustation (adjectival form: gustatory) is one of the traditional five senses . It refers to the capability to detect the taste of substances such as food, certain minerals, and poisons, etc . The sense of taste is often confused with the "sense" of flavor, which is a combination of taste and smell perception . Flavor depends on odor, texture, and temperature as well as on taste . Humans receive tastes through sensory organs called taste buds, or gustatory calyculi, concentrated on the upper surface of the tongue . There are five basic tastes: sweet, bitter, sour, salty and umami . Other tastes such as calcium and free fatty acids may also be basic tastes but have yet to receive widespread acceptance . The inability to taste is called ageusia . </P> <P> Smell or olfaction (adjectival form: olfactory) is the other "chemical" sense . Unlike taste, there are hundreds of olfactory receptors (388 according to one source), each binding to a particular molecular feature . Odor molecules possess a variety of features and, thus, excite specific receptors more or less strongly . This combination of excitatory signals from different receptors makes up what we perceive as the molecule's smell . In the brain, olfaction is processed by the olfactory system . Olfactory receptor neurons in the nose differ from most other neurons in that they die and regenerate on a regular basis . The inability to smell is called anosmia . Some neurons in the nose are specialized to detect pheromones . </P> <P> Touch or somatosensation (adjectival form: somatic), also called tactition (adjectival form: tactile) or mechanoreception, is a perception resulting from activation of neural receptors, generally in the skin including hair follicles, but also in the tongue, throat, and mucosa . A variety of pressure receptors respond to variations in pressure (firm, brushing, sustained, etc .). The touch sense of itching caused by insect bites or allergies involves special itch - specific neurons in the skin and spinal cord . The loss or impairment of the ability to feel anything touched is called tactile anesthesia . Paresthesia is a sensation of tingling, pricking, or numbness of the skin that may result from nerve damage and may be permanent or temporary . </P>

When are the five senses—taste smell touch hearing and sight—developed