Our ears are more than a place to hold up our glasses or display fashionable earrings. The ear is a complex part of the body made up of an intricate system of bones and hair follicles. One of the smallest parts of our body is responsible for such a large part of our survival in the everyday world. The ear is made up of five sections: the outer ear, the middle ear, the inner ear, the acoustic nerve, and the brain’s auditory processing center. To begin, the outer ear is the part of the ear that is visible on our heads, which is called the pinna. The pinna is responsible for collecting the sound vibrations. When a sound reaches your ear the first place it travels to is your eardrum. Before a sound vibration reaches the eardrum it travels through a thin canal, which is covered with tiny hairs and wax. The hair and wax in the ear canal help to keep out foreign debris such as dirt and bugs. The eardrum is the beginning of the middle. The eardrum is made up of a translucent fiber. Connected to the eardrum are three tine bones called the ossicles. When sound waves reach the eardrum the ossicles vibrate which produce mechanical sound waves. These waves are transmitted to the inner ear. The inner ear is comprised on many different parts, however the main vessel in the inner ear is the cochlea. The cochlea is the size of a pea and resembles the shape of a snail. The cochlea holds the Organ of Corti, which is the sensory receptor of the ear. Inside the organ of corti are tiny hairs, which act as the nerve receptors of hearing. The nerve receptors send messages to the brain about the sound such as the loudness and pitch.
( http://faculty.washington.edu/chudler/bigear.html, 6/25/03; please see Bibliography at the end of this unit)