As we hear

The size of the middle ear is eight times less than the external and is a small cavity inside the skull. Here is located the tympanic membrane, and the opposite part of the middle ear, connecting with the nose, a narrow tube. This gives you the ability to equalize the air pressure in the middle ear relative to the external environment. If the pressure outside is changing, our ears have to adapt to it.
In the cavity of the middle ear are three bones, each of which has a certain form. They are called the hammer, anvil, and stirrup. Air vibrations reflected from the tympanic membrane, coming from the Malleus to the stapes and the oval window of the vestibule that connects the middle and inner ear.
In the inner ear is a maze of three fluid-filled tubes, through which we feel the steady pressure. In addition, in the inner ear has a miniature spiral pipe, a curl, consisting of two channels and ducts. These channels and the fluid-filled. In the Strait also contains tiny sensory hair cells that covers a narrow membrane film. These cells and the membrane form of the organ of Corti.
He is a real hearing aid center. Vibrations through the cochlea, forcing the membrane to move back and forth. Moving, the membrane pulls on the hair cells and they send electrical signals through the auditory nerve to the brain. The brain decodes these signals and perceives them as sounds.