The Human Outer Ear
The outer ear is the external portion of the ear. It includes the pinna, the auditory canal and theeardrum.
The Middle Ear
The middle ear consists of three small bones called the ossicles: malleus (hammer), incus (anvil) and stapes (stirrup). These bones amplify and conduct the vibrations of the eardrum to the inner ear.
The Inner Ear
The inner ear includes thecochlea and the vestibular apparatus, the organ of balance.
How Hearing Works
Sounds are first collected by the outer ear. They pass through the auditory canal and cause the eardrum to vibrate.
The vibrations are sent to the inner ear by the bones of the middle ear. The inner ear transforms the mechanical vibrations into electrical impulses. The cochlea is full of fluid and contains tiny cells called hair cells. The hair cells send signals along the auditory nerve to the brain. These impulses are recognized and decoded by our brain as sound types.
Humans can generally hear sounds with frequencies between 20 Hz and 20,000 Hz. Human speech includes frequencies between 500 and 4000 Hz.
Animals can hear sounds with various frequencies. For example: the Elephant (17 - 10,000 Hz), the Monkey (110 - 45,000 Hz), the Mouse (1,000 - 90,000 Mhz), the Bat (3,000 - 120,000 Hz).