Three main parts of the ear help with hearing: the outer ear, the middle ear and the inner ear. The outer ear consists of the pinna, which is the visible portion of the ear, and the ear canal that leads to the eardrum. The pinna is responsible for collecting sound waves and funneling them into the ear canal, which amplifies certain frequencies and filters out others as it directs sound waves to the eardrum. The eardrum separates the outer ear from the middle ear. The middle ear is a small cavity between the eardrum and the inner ear. The middle ear contains three bones; they are the malleus (sometimes called hammer), the incus (sometimes called anvil) and the stapes (sometimes called stirrup). These three bones are connected together to form the ossicular chain which carries sound vibrations from the eardrum to the inner ear. The inner ear contains the cochlea, which resembles a snail shell. The cochlea turns the mechanical sound vibrations into electrical signals that are transmitted to the brain via the auditory nerve. The electrical signals are interpreted by the brain and recognized as sound.

Sound waves travel in all directions from their source through the air. Each part of the ear plays a role in hearing sound waves.

• The pinna captures sound waves from the air, focuses them, and directs them into the ear canal.
• The ear canal acts as a resonating tube, emphasizing certain frequencies that are important in speech.
• The sound waves strike the eardrum and cause the eardrum to vibrate.
• The small bones in the middle ear – the malleus, incus and stapes – amplify and transmit the vibrations from the eardrum to the oval window of the inner ear.
• When the oval window of the inner ear vibrates, it causes the fluid inside the cochlea to move. This movement causes the hearing hair cells to move. The hair cells are connected to nerve endings which convert this movement into electrical signals.
• The auditory nerve sends the electrical signals to the brain, where they are interpreted as sound.