The Ear and the Sense of Hearing

The organ for hearing sound is called the ear. It is one of the most complex and useful organs in our body. Hearing sounds is all about vibrations. Vibrations cause sound waves. For instance, if you knock on your table, the sound is produced as a result of vibrations from the impact. But the sound alone means nothing until we hear it, and our brains interpret what sound it is.

Here is the diagram of the whole hearing organ, The Ear.

The Ear
The Ear

The ear is composed of three parts. 

  1. The outer ear consists of the earflap (pinna or auricle), the ear canal, and the eardrum.
  2. The middle ear houses our body’s three smallest bones, the ossicles. 
  3. The inner ear consists of bony chambers called the Cochlea and Corti.

How does hearing occur?

The pinna is like a funnel, which directs sound to the ear canal and unto the eardrum. The ear canal has wax in it that helps trap infections and particles from getting deeper into the more sensitive parts of the organ.

Sound waves traveling through the ear canal reach the eardrum and bounces off, setting the eardrum to vibrate too. This sets off more vibrations of the ossicles (the three small bones called Hammer, Anvil, and Stirrup) inside of the middle ear.

The ossicles are connected to the cochlea, which is a long chamber, shaped like a garden snail and filled with a liquid. This chamber has a hair-like lining. As vibrations travel through the liquid in the chamber, the tiny hairs are stimulated. The hairs pick up the vibration signals from the liquid and send them to a special part of the brain for interpretation. The entire process happens within millions of a second.

Loud Noise

Powerful vibrations cause more activation of the hairs in the cochlea, and the brain understands it as a loud noise. Extreme vibrations can break (rapture) the eardrum and ossicles, causing hearing loss. Even household noises like sound systems, lawnmowers, and loud earphones can cause significant damage to the hearing organ. The ear is a useful organ, and you should take care of it by wearing sound-proof equipment when you are in noisy environments.

Infections (often caused by bacteria introduced into the ear by sticking things into the ear), drugs, and old age can also cause hearing loss.