Module 1 Lesson 3 - 8
Lesson 3 — Mechanoreception: The Ear
Consider this Scenario
Ethan was very excited to have a job as an assistant baggage handler at the airport. He drove the baggage trains as well as loaded and unloaded suitcases and parcels from airplanes. However, he found that the ear protection he was supposed to wear was hot and cumbersome. He took it off whenever he could, and sometimes he forgot to put it back on when the big jets came in or took off. After two years on the job, he began to have difficulty hearing. A hearing clinic suggested he purchase a very expensive new type of hearing aid that would improve his hearing greatly. Ethan was very upset because his medical plan did not pay for hearing aids.
Do you think that hearing aids should be covered by medical plans? Keeping Ethan's story in mind, think of reasons they should and reasons they should not. Often, an examination question poses an ethical dilemma such as this. Be prepared to support both sides of such issues.
Example:
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Lesson Summary
This lesson investigated the following focusing questions:
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What are the main parts of the ear that facilitate responses to sound in the environment?
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How do the structures of the ear affect ability to maintain balance within the changing environment?
You should be familiar with the structures and functions of the outer, middle, and particularly the inner ear. Located in the inner ear, both the cochlea, adapted for hearing, and the semicircular canals, the utricle, and the saccule, adapted for maintaining balance, rely on specialized hair cells to change mechanical energy of sound or movement to the electrochemical energy of a nerve impulse. The structures of the outer and middle ear conduct and amplify sound waves so that pressure waves can be produced in the cochlea of the inner ear. The frequency of a sound wave results in the perception of pitch, but the amplitude (height) of the sound wave results in the perception of loudness. Conduction deafness and perception (nerve) deafness result from a dysfunction in the hearing apparatus. Both rotational balance and gravitational balance are maintained by the semicircular canals, the utricle, and the saccule. Technologies such as hearing aids and cochlear implants help deal with hearing loss.