(N/A) $1$. The outer ear $(PINNA)$ collects sound waves from the surroundings.
$2$. These sound waves travel through the auditory canal to the eardrum $(TYMPANIC \text{ } MEMBRANE)$.
$3$. When a compression reaches the eardrum, the pressure increases, pushing it inward. When a rarefaction reaches it, the pressure decreases, pulling it outward. This causes the eardrum to vibrate.
$4$. These vibrations are amplified several times by the three small bones $(MALLEUS, \text{ } INCUS, \text{ } STAPES)$ in the middle ear.
$5$. The middle ear transmits these amplified pressure variations to the inner ear.
$6$. In the inner ear, the $COCHLEA$ converts these pressure variations into electrical signals.
$7$. These electrical signals are sent to the brain via the auditory nerve, where the brain interprets them as sound.