Sound travels through the air in waves first striking the outer ear which is the part visible on the head. It’s also known as the pinna or auricle. The outer ear’s shape helps to collect sound and direct it inside the head toward the middle and inner ears. Along the way, the shape of the ear helps to increase the volume of the sound and help locate which direction it is coming from.

From the outer ear, sound waves travel through a small tube approx. 2.5cm known as the ear canal. In people, this tiny tube is about 2.5 centimeters (1 inch) long.
The ear drum or tympanum is stretched tightly across the end of the ear canal inside the head. As sound waves reach the ear drum, they vibrate its membrane. This triggers pressure waves that swell into the middle ear.

Inside the middle ear is a small cavity with three tiny bones. Those bones are the malleus (which means “hammer” in Latin), the incus (which means “anvil” in Latin) and the stapes (which means “stirrup” in Latin). These three bones are known as ossicles. They are the smallest bones in the human body. The stapes (STAY-pees), for instance, is only 3 millimeters (0.1 inch) long! These three bones work together to receive sound waves and transmit them on to the inner ear.Inside this inner ear is a fluid-filled, snail-shaped structure. It’s called the cochlea. Inside it stand ranks of microscopic “hair” cells. They contain bundles of tiny, hair-like strands embedded in a gel-like membrane. When sound vibrations enter the cochlea, they make the membrane and its hair cells sway to and fro. Their movements send messages to the brain that register the sound as any of many distinct pitches.

These hair cells are fragile, over time, they begin to weaken and disappear, this can be caused by exposure to loud noise and aging. People begin to lose the ability to detect certain sounds. Hair cells that respond to high-pitched sounds tend to die off first.
When one dies, it's gone forever. That is why it is so important to protect your ears from exposure to loud noises and also have your hearing health tested.

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