Grandma Moon Speaks: The Human Ear Part 1

Topics Covered:

  • The 3 Regions of the Human Ear
  • The Pinna and the Auditory Canal
  • The Ear Drum

One good thing about music, when it hits you, you feel no pain – Bob Marley

If the eye is designed for just one thing – sight, then the ear is designed for three – hearing, balance and positioning.

Here we are only concerned with one of these functions – hearing. If you ask most people to point to an ear, what they’ll most probably point to is the Pinna.

The Pinna is made by cartilage (a flexible connective tissue). The reason it’s shaped so oddly is because it funnels the sound into the auditory canal. Imagine how an antenna catches a television signal.

This part of the ear is called the External Division, the one we have access to with our ear buds, ear phones and fingers.

After the long voyage through the canal, the sound waves finally hit something – a dead end as far as they are concerned. But for us, what they hit is one of the most important parts of the ear – the Ear Drum.

Imagine continuous waves of sound hitting a highly sensitive drum, like ocean waves hitting the shore. The energy from the waves is absorbed continuously by the ear drum, which is important; because if they bounced back they would mingle with the next set of waves and distort the sound.

The ear drum (tympanic membrane) just throbs like a heart whenever it is excited, which is all the time. Unlike eyes, our ears don’t sleep. They are always working.

Where the ear drum ends, the Middle Division of the Ear begins. This part is not accessible to foreign objects, and is a highly sensitive region whose purpose is to transfer the throbs of the ear drum into the third region – the Inner Division.

The middle ear is an air-filled cavity that has three bones (called Ossicles): the hammer (malleus), the anvil (incus), and the stirrup (stapes).

It’s a physical connection between these three bones and the ear drum. These bones help to amplify the tiny vibrations of the ear drum to nearly six times its original intensity.

When the stapes moves, it causes movement of a fluid within the cochlea (a portion of the inner ear). This bone channels the sound pressure to one end of the cochlea, and protects the other end from being struck by sound waves.

Now the sound is ready to be heard.

Takeaways:

  • The ear is designed for three functions – hearing, balance and positioning.
  • The ear system can be divided into three parts – the External, Middle and Inner regions.
  • The Inner region comprises of the Pinna, the Auditory canal and the Ear Drum.
  • The Middle region comprises of three bones that amplify the sound waves by nearly six times.

Links for further study:

Next: The Human Ear Part 2
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