How is sound heard?

Answer 1

sound is made by vibration and our ears have a special thing that transmits it it to sound we understand.

answer 2 For simplicity we consider our ears are divided into three parts .

The Outer Ear stops at the eardrum. Which transfers the sound to the middle ear.

The Middle Ear contains three small bones, the tiniest in the body, the Incus, Malleus, and Stapes. The first two are coupled in such a way that they operate as a mechanical lever to reduce the sensitivity of the ear to loud sounds.

The stapes is attached to the Cochlea, the Inner Ear, via a small membrane window. This transfers the vibration of sound into the fluid-filled inner ear. The cochlea resembles a coiled up shell (hence the name) tapering to the far end.

The cochlea is divided along its length by a membrane (not considered further here) and along its length there are thousands of fine hairs, each attached to a Hair Cell. When the hairs move, they excite a signal from the Hair cell, and our Brain interprets this as sound.

Addenda. Also in the ear, lie the balance organs, common to all vertebrates, consisting of three semicircular canals (tubes), fluid filled. One for each of the x,y,z, directions. These each have small bone-like materials in them resting on a pad of nerves, and signal to our brain the attitude of the body.

Beautifully developed in birds, and poorly developed in fish; for it doesn't matter much if they fall over.

This association with the balance organs, possibly explains the very early development in the human embryo of the Neural Groove, as early as an embryo of a few cm.

Posit. Bird eggs are well known to need frequent turning over, presumably something essential to development, and the early balance organs and neural development may serve some need of a variable attitude.

Answer 2

You ears either interpretates it directly, or it's caught by the ears and then sent to the brain which then interpretates it. (sorry, I'm not sure which)

The interpretation has probably been developed through natural evolution, if we are to believe in some evolution theory, that since early primate evolution there's been a desire or necessity to communicate, so throughout the years they've slowly developed protocols and the necessary hardware (organs) to finally communicate.

And your ears are, supposedly, like Tuning Forks - so it tries adjusting itself to the sound(-waves) it encounters. Without this ability we'd barely understand anything!

Answer 3

The eardrum is moved by sound waves, causing the bones of the middle ear to vibrate. These bones amplify the movement and push on the oval window, creating vibrations in the fluid filled cochlea. The little hairs inside the cochlea are mechnoreceptors and they release chemical neurotransmitters when the vibrating fluid causes them to move. The sound is hence transformed into nerve impulses and they are carried by the auditory nerve to the brain.