How do we hear?

In this blog, I will talk about and explore how our hearing system works. The human ear is an extremely delicate and complicated natural device, so much that it is truly fascinating to know of how it works and almost impossible to believe so much actually happens in such a small place.

The anatomy of the human ear exists in three major parts extensively known as - the outer, middle, and inner ear. The part that we can see, along with the ear canal, is known as the outer ear. The eardrum can be found towards the end of the ear canal which separates the outer from  what is known as the middle ear. It is small cavity that consists of three tiny bones known as the ‘auditory ossicles’. The auditory ossicles is made up of the malleus (aka hammer), incus (aka anvil), and stapes (aka stirrup). Then we have the inner ear which in reality is two different components: the cochlea, which handles the hearing aspect, and the vestibular system, which helps controls our balance. The cochlea is a tiny chamber which is almost snail-shaped which is attached to the auditory nerve which leads to the brain, where as the vestibular system is made up of many different tubes and sacs. The inner ear is also often known as the ‘labyrinth’.

The outer ear, also called as the pinna enhances our hearing. The is the soft cartilage structure which an on a day to day basis would call our ‘ear’ and the part which someone decided was a good place to poke a hole and hang jewelry and everyone followed?! What the pinna actually does for us is that it helps our brain identify the direction from where the sound is coming from.

“What happens to us on the inside when we hear a noise?” you may ask. First, a series of vibrations known as ‘sound waves’ passes through all parts of our ear. When the vibration strikes the eardrum, it vibrates with response and sends the vibrations onwards to the auditory ossicles. The three small bones there then amplify the sound and moves them along to the cochlea, which is lined with sensory receptors and is filled with fluids. The vibrations then cause the fluid movement, which then in turn moves our sensory receptors. The sensory receptors then send an electric signal to our brains, where it is translated into a sound that we can understand.  It might seem like a complicated and long process, but as we know, this all happens so instantly as soon as sound waves are created that we don’t even realize it’s happening!

Have you at any point of time heard a ring in your ear and you just think to yourself “what is that??” What is actually happening is that one of your numerous hair cells in your ear has just vanished. The tragic part being, these cells are key in our hearing and can never come back.So next time you hear a ring in your ear you will realize that a hair cell simply died.

Another aspect you might be wondering about is how hearing aids fit into all of this. The simple answer is that hearing aids actually amplify sounds and direct them into the ear. While there are many different types, almost all hearing aids have the same main principle and components which are –

·         a microphone

·         an amplifier, and

·         a receiver/speaker

which puts this into the category of audio

 

Refrences

How Hearing Works: Your Guide to the Human ear. (audicus). Retrieved March 15, 2016, from https://www.audicus.com/how-hearing-works-your-guide-to-the-human-ear/ 

The Auditory System. (n.d.). Retrieved October 15, 2017, from https://explorable.com/auditory-system

[The human ear - a system of human hearing mechanism.] [Photograph]. (n.d.). Retrieved from https://informatics.buzdo.com/specific/theater-1.htm

[Working of a hearing aid device] [Photograph]. (Joe O'Donnell). Retrieved from http://www.ssc.education.ed.ac.uk/courses/deaf/aud2ad.html