The ear is consists of three parts, the outer, middle and inner ear. All three parts are imperative for perceiving sound by working together to move sound from the outer ear via the middle and into the inner part of the ear. Ears also help to maintain your balance.
The outer ear includes:
Auricle (cartilage protected by skin placed on opposite sides of the head)
Auditory canal (also referred the ear canal)
Eardrum outer layer (also referred the tympanic membrane)
The outer portion of the ear stores sound. Sound moves through the auricle and the auditory canal, a little duct that ends at the ends at the eardrum.
The pinna is the single visible part of the ear (the auricle). It has a distinct helical shape. It is the first portion of the ear that responds to sound. The function of the pinna is to act as a funnel which aids in channeling sound further and deeper into the ear.
Without this funnel, the sound would take a more direct round to into the auditory canal. This would be difficult, and inefficiency as much of the sound would be lost making it hear to hear and understand the sounds.
The pinna imperative because of the difference in pressure inside versus outside the ear. The resistance of the air is typical higher inside the ear than outside because the air within the ear is solid and therefore under higher pressure.
For the sound waves to enter the ear in the most effective method, the resistance can not be excessively high. The pinna helps by adapting to the difference in pressure inside the ear. The pinna functions as an intermediate link which makes the transition smoother and less brutal allowing more sound to pass through the auditory canal (meatus)
The Ear Canal – the Auditory Canal
After the sound waves have circulated through pinna, they travel between two and three centimeters into the auditory canal, then hit hitting the eardrum, also referred to as the tympanic membrane. The function of the ear canal is to transfer sound from the pinna to the eardrum.
The eardrum (also referred to as the tympanic membrane), is a membrane at the end of the auditory canal and indicates the start of the middle ear. The eardrum is tremendously delicate, and compression from sound waves creates eardrum vibrations. For protection, the auditory canal is marginally curved making it more difficult for particles, insects to reach the reach the eardrum. Also, earwax(cerumen) in the auditory canal also aids in keeping unwanted materials like dirt dust and insects out of the ear.
Along with protecting the eardrum, the auditory canal also serves as a natural hearing aid; that mechanically amplifies low and less penetrating sounds of the human voice. This ability allows the ear compensate for some of the weakness of the human voice and makes it ear to hear and understand normal conversations.