Hearing explained

How do we hear?

Ever wondered how hearing works? From the sound waves that enter the outer ear to the interpretations made by our brains, it’s a fascinating process from start to finish. Learn more about the key parts of the ear and how they work together as we explain how we hear.

The role of the eardrum

When thinking about how our hearing works, it’s best to go back to the very first stage in the hearing process. All the sounds around us, whether they be voices, the media we watch and listen to, or other environmental noises, are first collected by the outer ear. Also known as the pinna or auricle, this is the part of the ear that is most visible to us. Its unique shape helps to funnel sound waves into the ear canal. 

On entry into the ear canal, sound waves are amplified and travel through to the eardrum. Also known as the tympanic membrane, the eardrum is a small, flexible membrane that separates the outer ear and the middle ear. Its primary function is to convert the sound waves transmitted through the air into vibrations after they enter the ear, but it also helps to protect the middle ear from bacteria, dirt and debris that may enter the ear.

The sound vibrations

When sound waves meet the eardrum, they cause the membrane to vibrate. The eardrum is quite sensitive and can detect sounds of all volumes, from whispers to stadium rock performances, with each making the eardrum vibrate in a unique way. These sound vibrations assist in the next step in the hearing process, setting the middle ear ossicles into motion.

Acoustic nerve and sounds interpretation

Sometimes referred to as the auditory nerve, the acoustic nerve transports the electrical impulses generated by the hair cells to the brain. They travel along the nerve, through the brainstem and onto the auditory cortex. Once the impulses reach the auditory cortex, the brain interprets the messages it has received, translating them into the recognisable sounds we understand.

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Book your appointment in one of our clinics. Regularly checking your hearing quality is an important step in maintaining your overall health and wellness. This is a good place to start on your hearing health and the test involves checking your hearing.

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Anatomy of your ear

There are three main sections; the inner ear, the middle ear, the outer ear.

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Signs of hearing loss

How do I know I have a hearing problem?

The cochlea and the ossicles of the ear

The ossicles of the ear are made up of three tiny bones: the stapes (stirrup), the incus (anvil) and the malleus (hammer). They are the smallest bones in the body and work together to amplify sound further. When the eardrum vibrates, the ossicles start to move, transferring the vibrations through to the cochlea.

The cochlea is a spiral-shaped organ situated within the inner ear. It is filled with fluid and, when vibrations are transferred to the cochlea by the middle ear ossicles, the fluid within the organ starts to move. The main function of the cochlea is to stimulate microscopic hair cells for the next stage of sound processing, with the wave-like movements of the fluid helping to do so.

Hair cells and neural signals

There are thousands of hair cells in the cochlea, helping to detect a variety of sounds. Some may pick up higher-pitched sounds, while others may only detect lower-pitched sounds. The hair cells located close to the wide end of the cochlear tend to detect high-pitched sounds, while cells found closer to the centre of the organ primarily detect low-pitched sounds.

Hair cells are activated through the motion of the fluid in the cochlea. This movement causes microscopic projections located on the haircells; known as stereocilia to move and bend. As they bend, small channels in the stereocilia open, allowing certain chemicals to enter the hair cells. The hair cells are then able to produce electrical impulses, which are transmitted to the acoustic nerve.

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