About functional evolution of peripheral part of the auditory system

Functional evolution of the peripheral part of the auditory system is considered. The key point of the appearance of a possibility of analysis of sound waved is formation in the course of evolution of cells with protoplasmic processes (sensillae)—the hair cells—that are transformed into auditory receptors. The fundamental moment is the emergence in evolution of the specialized ionic medium (endolymph) surrounding the auditory receptors. This medium is necessary for generation of receptor potential due to mechanical deformations of the auditory receptor. The characteristic feature of functional evolution of the peripheral part of the auditory system is the many-time repetition in the course of evolution of the main devices to detect and to distinguish sounds. This indicates recapitulation in evolution not only of the central parts of the brain (including central regions of the auditory system), but also of its peripheral part.