How We Hear – The Human Ear
The human ear collects, amplifies, processes and delivers sound to the brain. Ears also help maintain balance.
The Human Ear is Divided Into Three Main Sections:
- The Outer Ear
- The Middle Ear
- The Inner Ear
The Outer Ear
The outer ear consists of the ear canal (auditory canal) and auricle. The auricle is commonly referred to as the earlobe or pinna. The auricle is designed to reduce background noise as well as collect and naturally amplify acoustic energy or sound waves. The auricle directs the sound waves to the ear canal where they are re-amplified and received by the eardrum (tympanic membrane).
The outer ear also contains cerumen, otherwise known as ear wax. Cerumen contains properties that can prevent infections, maintain sterile conditions in the ear canal, and deter foreign bodies or insects from entering deep into the ear. Excess ear wax should be removed to maintain optimum hearing aid performance. The removal of ear wax is recommended to occur under the supervision of a physician.
The Middle Ear
The middle ear includes the smallest bones in the human body known as the ossicles.
The Ossicles Are Named Individually:
- The Incus (Anvil)
- The Malleus (Hammer)
- The Stapes (Stirrup)
When sound is directed to the eardrum, the eardrum vibrates and causes the ossicles attached to move simultaneously.
The middle ear is responsible for converting acoustic energy (sound waves from the outer ear) into mechanical energy (movement of the ossicles).
The Inner Ear
The inner ear mainly contains the cochlea, vestibular system and hearing nerve. The inner ear is located in the temporal bone.
- The cochlea is snail shaped and contains two fluids called endolymph and perilymph
- The vestibular system consists of the saccule and utricle. It also contains three semicircular canals which provide lateral, horizontal and vertical balance
- The hearing nerve (cochlear nerve) transmits impulses to the brain.
The inner ear is responsible for converting mechanical energy from the middle ear into electrical nerve impulses that are transmitted to the auditory complex in the brain. The end result is you hearing a sound.