The hearing - the body's ability to perceive and distinguish the sound vibrations. This ability is auditory (sound) analyzer.
Human hearing the available area of sounds with a frequency of 16 to 20 000 Hz. Minimum volume that can cause subtle feeling of the audible sound is called the threshold of auditory sensation. Hearing sensitivity, or hearing acuity is determined by the value of hearing threshold feeling less than the threshold value, the higher the hearing acuity. By increasing the strength of the sound, the feeling of sound volume increases, but when reaching power of the sound of a certain magnitude increase the volume is terminated and there is a feeling of pressure or even pain in the ear. The power of sound, which comes these unpleasant sensations is called pain threshold or threshold of discomfort. Hearing sensitivity is characterized not only by the value of hearing threshold of sensation, but the size of differential or differential threshold, i.e. the ability to discriminate between sounds in strength and height (frequency).
When exposed to sounds and hearing acuity varies. The strong sounds leads to a lowering of the hearing; in conditions of peace, hearing sensitivity quickly (10-15 seconds) recovering. This physiological adaptation of the auditory analyzer to the effect of sound stimulus is called auditory adaptation. Adaptation should be distinguished auditory fatiguearising from prolonged exposure to intense sounds, and characterized by a temporary reduction in hearing sensitivity with a longer recovery period normal hearing (several minutes or even hours). Frequent and prolonged irritation of the hearing body strong sounds (e.g., noisy manufacturing) can lead to irreversible reduction hearing. To prevent persistent hearing working bustling shops must use a special plug - by protivochumnoe (see).
The presence of a pair of ear in humans and animals provides the ability to locate the source of the sound. This ability is called binaural hearing or ototopical. Unilaterally to defeat hearing ototopical greatly disturbed.
Specific feature of the human ear is the ability to perceive sounds of speech not only as a physical phenomenon, but as a distinctive unit - phoneme. This ability is provided by the person hearing the speech center, located in the left temporal lobe of the brain. When you turn off this centre of perception of sounds and murmurs, part of speech, is retained, but the distinction between them as speech sounds, i.e., speech understanding, it becomes impossible (see Aphasia, Alalia).
For research of hearing using different methods. The simplest and most accessible is the study by speaking. An indicator of the severity of hearing is the distance at which differ in certain elements of speech. Practically hearing is normal if the whispered it varies at a distance of 6 - 7 m
To obtain more accurate data about the state of the hearing applied research using tuning forks (see) and audiometer (see Audiometry).