The auditory center of the brain plays a critical role in this process, but the ear is no less important. After all, without it, there's no input for the brain to interpret. Today, we're going to take a closer look at this essential organ, and how it works.
audiologist explaining the anatomy of the human ear and hearing loss

The Hearing Organ

Sound waves are, at their core, little more than vibrations in the air. It's through hearing that we interpret and assign meaning to them. To understand the path a sound wave takes from origin to interpretation, however, we must first understand the ear itself. 

There are three main components of the body's hearing organ, each with its own role to play in the hearing process.
Diagram of the anatomy of the human ear and auditory system

How Does Hearing Work?

The Outer Ear
Arguably the simplest part of the hearing process, the outer ear has a single job. It gathers and funnels soundwaves via the auricle (A, B, and D on the image to the right). These sounds travel down the auditory canal towards the middle ear.

Interestingly, the outer ear's unique shape makes it ideally suited for this job. It acts as a resonator for soundwaves, while at the same time muting unnecessary background noise.
The Middle Ear
Once a sound wave proceeds through the auditory canal, it rebounds off the eardrum. This is where the middle ear comes in. The vibrations from the sound then travel through the ossicles, known respectively as the malleus, the incus, and the stapes.

As some of the smallest bones in the human body, the ossicles are responsible for amplifying and transmitting sound from the middle ear to the inner ear. The middle ear also contains an organ known as the eustachian tube, which connects to the sinuses to both equalize pressure in the middle ear and drain any fluid buildup.
The Inner Ear
Finally, once sound travels through the ossicles, it reaches the inner ear, where it travels through the cochlea. A spiraling organ bearing a resemblance to a snail's shell, the cochlea consists of three fluid-filled canals lined with tiny hairs. Each grouping of these hairs is keyed to a particular frequency of sound.

When a group of hairs in the cochlea is stimulated, they transmit an impulse to the brain via the auditory nerve.

In addition to hearing, the inner ear has two other important roles. It maintains balance and equilibrium via the vestibule and semicircular canals, respectively. This is one of the primary reasons why ear infections and severe hearing damage can lead to feelings of vertigo — because they cause these two important components to go haywire.
Signal Conduction to the Brain
Even when the sound waves have arrived in the inner ear they still have no meaning. Once conducted to the auditory nerve, the sound waves are converted to electrical signals that first hit the brain stem. The signal is conducted to the areas of the brain responsible for emotional assessment. Thus meaning is attached to tones which are then connected to existing patterns in the cortex. This allows humans to understand speech, recognize the voice of a friend, and judge hazardous situations.

This means that our hearing only works if the conduction of signals from one station to the other works perfectly and only once oscillating air has been turned into a warning signal, pleasant music, or a coherent sentence.

Air Conduction vs. Bone Conduction

Although air conduction is the primary mechanism of hearing, sound can also reach the inner ear through a secondary route, known as bone conduction. This is typically not as effective as air conduction, it has some application in treating hearing loss, particularly in cases where the eardrum is extremely damaged. Interestingly, bone conduction is the reason why our voices sound different to us when we listen to recordings of ourselves — instead of hearing our voices through both air conduction and bone conduction, we hear them only via air conduction.