Chapter 5
Anatomy & Physiology of Hearing
Study of the auditory mechanism requires many visual aids and lots of imagination because of
the scale of the structures. Many of the drawings from the text are in the Lab Guide section, and
numerous excellent photographs of the cochlear structures are available. One of my all-time
favorite sources is W. A. Yost, Fundamentals of Hearing: An Introduction, 5th ed. (New York:
Academic Press, 2006), which has excellent micrographs of hair cells, the organ of Corti, and
noise-induced damage.
Hearing Class Activity 1
Lecture Discussion Questions
1. The term transducer is used a lot in hearing. What is being transduced?
2. Of what use is the pinna?
3. What physical protection does the external auditory meatus provide?
4. What acoustical benefit is gained from having an external auditory meatus?
5. What are the bones of the middle ear, from distal to medial?
6. What are the smallest muscles of the body?
7. Which muscle of the middle ear is innervated by the V trigeminal nerve?
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8. Which muscle of the middle ear is innervated by the VII facial nerve?
9. What benefit is there to having two different innervation sources for muscles that are
separated by only 1 cm?
10. What membrane separates the scala vestibuli and scala media?
11. What membrane separates the scala tympani and scala media?
12. The hair cells are innervated by which nerve?
13. Information from the VIII vestibulocochlear nerve arises from the hair cell. Trace (verbally)
the physical pathway taken by the nerve from an outer hair cell.
(The nerve fiber courses across the tunnel of Corti and enters the perforations of the spiral
lamina, where it combines with other fibers of the VIII nerve. The cell bodies of the VIII
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Hearing Class Activity 2
Decibels
Admittedly, the decibel is not a topic that students appreciate, but successful contact with, and
understanding of, the decibel is very useful. Although this topic is covered in most hearing
science or beginning audiology courses, it never hurts to cover it again. Hearing Lab 2 is a
worksheet designed to bring students into easy, nonpunitive contact with the decibel. When that
is done, an easy step is to calculate the decibel gain from the area ratio and lever ratio by
plugging that into the decibel calculation. Again, it may be too esoteric for your A&P class, but
the materials are provided within the lab activities should you want to use them. (Note: This
activity was produced as a result of funding by the Fund for Improvement of Postsecondary
Education [FIPSE No. P116B90965-90] . It is designed to be a class activity, and is best done in
small groups. I have had students really perk up after succeeding with the decibel!)
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Hearing Class Activity 3
Semicircular Canal Model
One of my colleagues at Idaho State University (Dr. Jeff Brockett) devised an ingenious device
for demonstrating the function of the semicircular canals. He fashioned three polyethylene tubes
(clear) with colored liquid in them, representing each of the three axes of multidimensional
space. He then placed some marbles in the tubes to show the effects of gravity on the fluid. It’s a
great demonstration, and worth re-creating.
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Hearing Class Activity 4
Available Software
Through a grant from the Fund for Improvement of Postsecondary Education (FIPSE No.
P116A80462), we have developed a software package for instrumentation in audiology that is
available free of charge. The AUDIN self-study program in instrumentation admittedly was
designed with graduate students in audiology in mind, but it has some good basic chapters on
auditory physiology that might be useful in your discussion. It is too large to fit on this CD, but
you may receive a free copy by mail. Please send an e-mail to seikel@isu.edu requesting the
AUDIN software, and we’ll send you a CD.
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Copyright ©2014 Delmar, Cengage Learning. All Rights Reserved.
Hearing Class Activity 5
Round-Robin Quiz
In the Round-Robin section for these chapters, you’ll find several images from the text with
labels conveniently removed (a key for your use follows each image). A quiz based on these
images gives students an opportunity to show what they know, or to learn what they need to
know! As with other scanned images in this set of materials, the scans are high-resolution images
and can be enlarged or copied into your PowerPoint presentation for ease of use.
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Hearing Class Activity 6
Video Tour of the Ear Canal
My colleague at Idaho State University, Jeff Brockett, Ph.D., produced a splendid MPEG video
tour of the outer ear and tympanic membrane; we were unable to put it on this CD because of
space restrictions. We would be more than happy to send it to you, free of charge, if you send an
e-mail request to seikel@isu.edu.