Anatomy and Physiology: Special Senses – The EAR
Hearing is one of the major senses and like vision is important for distant warning and communication. It can be used to alert, to communicate pleasure and fear. It is a conscious appreciation of vibration perceived as sound. In order to do this, the appropriate signal must reach the higher parts of the brain.
Functions of the ear
The ears are paired sensory organs comprising the auditory system, involved in the detection of sound, and the vestibular system, involved with maintaining body balance or the equilibrium. The ear divides anatomically and functionally into three regions: the external ear, the middle ear, and the inner ear. All three regions are involved in hearing. Only the inner ear functions in the vestibular system.
- SOUND DETECTION. The function of the ear is to convert physical vibration into an encoded nervous impulse. It can be thought of as a biological microphone. Like a microphone the ear is stimulated by vibration: in the microphone the vibration is transduced into an electrical signal, in the ear into a nervous impulse which in turn is then processed by the central auditory pathways of the brain.
- MAINTAINING BODY BALANCE or EQUILIBRIUM. The prime function of the vestibular system is to detect and compensate for movement. This includes the ability to maintain optic fixation despite movement and to initiate muscle reflexes to maintain balance.
Anatomy of the Ear
The ear is divided into three major areas: the outer or external ear, the middle ear and the inner or internal ear. The outer and middle ear are involved with hearing only whilst the inner ear functions both equilibrium and hearing.